diff --git a/backend/main.py b/backend/main.py
index c4f77e4..33b77c6 100644
--- a/backend/main.py
+++ b/backend/main.py
@@ -115,6 +115,10 @@ app.include_router(alerts.router)
 from backend.routers import recurring_schedules
 app.include_router(recurring_schedules.router)
 
+# Fleet Calendar router
+from backend.routers import fleet_calendar
+app.include_router(fleet_calendar.router)
+
 # Start scheduler service and device status monitor on application startup
 from backend.services.scheduler import start_scheduler, stop_scheduler
 from backend.services.device_status_monitor import start_device_status_monitor, stop_device_status_monitor
diff --git a/backend/migrate_add_job_reservations.py b/backend/migrate_add_job_reservations.py
new file mode 100644
index 0000000..01d4b4b
--- /dev/null
+++ b/backend/migrate_add_job_reservations.py
@@ -0,0 +1,103 @@
+"""
+Migration script to add job reservations for the Fleet Calendar feature.
+
+This creates two tables:
+- job_reservations: Track future unit assignments for jobs/projects
+- job_reservation_units: Link specific units to reservations
+
+Run this script once to migrate an existing database.
+"""
+
+import sqlite3
+import os
+
+# Database path
+DB_PATH = "./data/seismo_fleet.db"
+
+
+def migrate_database():
+    """Create the job_reservations and job_reservation_units tables"""
+
+    if not os.path.exists(DB_PATH):
+        print(f"Database not found at {DB_PATH}")
+        print("The database will be created automatically when you run the application.")
+        return
+
+    print(f"Migrating database: {DB_PATH}")
+
+    conn = sqlite3.connect(DB_PATH)
+    cursor = conn.cursor()
+
+    # Check if job_reservations table already exists
+    cursor.execute("SELECT name FROM sqlite_master WHERE type='table' AND name='job_reservations'")
+    if cursor.fetchone():
+        print("Migration already applied - job_reservations table exists")
+        conn.close()
+        return
+
+    print("Creating job_reservations table...")
+
+    try:
+        # Create job_reservations table
+        cursor.execute("""
+            CREATE TABLE job_reservations (
+                id TEXT PRIMARY KEY,
+                name TEXT NOT NULL,
+                project_id TEXT,
+                start_date DATE NOT NULL,
+                end_date DATE NOT NULL,
+                assignment_type TEXT NOT NULL DEFAULT 'quantity',
+                device_type TEXT DEFAULT 'seismograph',
+                quantity_needed INTEGER,
+                notes TEXT,
+                color TEXT DEFAULT '#3B82F6',
+                created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+                updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+            )
+        """)
+        print("  Created job_reservations table")
+
+        # Create indexes for job_reservations
+        cursor.execute("CREATE INDEX idx_job_reservations_project_id ON job_reservations(project_id)")
+        print("  Created index on project_id")
+
+        cursor.execute("CREATE INDEX idx_job_reservations_dates ON job_reservations(start_date, end_date)")
+        print("  Created index on dates")
+
+        # Create job_reservation_units table
+        print("Creating job_reservation_units table...")
+        cursor.execute("""
+            CREATE TABLE job_reservation_units (
+                id TEXT PRIMARY KEY,
+                reservation_id TEXT NOT NULL,
+                unit_id TEXT NOT NULL,
+                assignment_source TEXT DEFAULT 'specific',
+                assigned_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+                FOREIGN KEY (reservation_id) REFERENCES job_reservations(id),
+                FOREIGN KEY (unit_id) REFERENCES roster(id)
+            )
+        """)
+        print("  Created job_reservation_units table")
+
+        # Create indexes for job_reservation_units
+        cursor.execute("CREATE INDEX idx_job_reservation_units_reservation_id ON job_reservation_units(reservation_id)")
+        print("  Created index on reservation_id")
+
+        cursor.execute("CREATE INDEX idx_job_reservation_units_unit_id ON job_reservation_units(unit_id)")
+        print("  Created index on unit_id")
+
+        conn.commit()
+        print("\nMigration completed successfully!")
+        print("You can now use the Fleet Calendar to manage unit reservations.")
+
+    except sqlite3.Error as e:
+        print(f"\nError during migration: {e}")
+        conn.rollback()
+        raise
+
+    finally:
+        conn.close()
+
+
+if __name__ == "__main__":
+    migrate_database()
diff --git a/backend/migrate_add_tbd_dates.py b/backend/migrate_add_tbd_dates.py
new file mode 100644
index 0000000..d205624
--- /dev/null
+++ b/backend/migrate_add_tbd_dates.py
@@ -0,0 +1,89 @@
+"""
+Migration: Add TBD date support to job reservations
+
+Adds columns:
+- job_reservations.estimated_end_date: For planning when end is TBD
+- job_reservations.end_date_tbd: Boolean flag for TBD end dates
+- job_reservation_units.unit_start_date: Unit-specific start (for swaps)
+- job_reservation_units.unit_end_date: Unit-specific end (for swaps)
+- job_reservation_units.unit_end_tbd: Unit-specific TBD flag
+- job_reservation_units.notes: Notes for the assignment
+
+Also makes job_reservations.end_date nullable.
+"""
+
+import sqlite3
+import sys
+from pathlib import Path
+
+def migrate(db_path: str):
+    """Run the migration."""
+    print(f"Migrating database: {db_path}")
+
+    conn = sqlite3.connect(db_path)
+    cursor = conn.cursor()
+
+    try:
+        # Check if job_reservations table exists
+        cursor.execute("SELECT name FROM sqlite_master WHERE type='table' AND name='job_reservations'")
+        if not cursor.fetchone():
+            print("job_reservations table does not exist. Skipping migration.")
+            return
+
+        # Get existing columns in job_reservations
+        cursor.execute("PRAGMA table_info(job_reservations)")
+        existing_cols = {row[1] for row in cursor.fetchall()}
+
+        # Add new columns to job_reservations if they don't exist
+        if 'estimated_end_date' not in existing_cols:
+            print("Adding estimated_end_date column to job_reservations...")
+            cursor.execute("ALTER TABLE job_reservations ADD COLUMN estimated_end_date DATE")
+
+        if 'end_date_tbd' not in existing_cols:
+            print("Adding end_date_tbd column to job_reservations...")
+            cursor.execute("ALTER TABLE job_reservations ADD COLUMN end_date_tbd BOOLEAN DEFAULT 0")
+
+        # Get existing columns in job_reservation_units
+        cursor.execute("PRAGMA table_info(job_reservation_units)")
+        unit_cols = {row[1] for row in cursor.fetchall()}
+
+        # Add new columns to job_reservation_units if they don't exist
+        if 'unit_start_date' not in unit_cols:
+            print("Adding unit_start_date column to job_reservation_units...")
+            cursor.execute("ALTER TABLE job_reservation_units ADD COLUMN unit_start_date DATE")
+
+        if 'unit_end_date' not in unit_cols:
+            print("Adding unit_end_date column to job_reservation_units...")
+            cursor.execute("ALTER TABLE job_reservation_units ADD COLUMN unit_end_date DATE")
+
+        if 'unit_end_tbd' not in unit_cols:
+            print("Adding unit_end_tbd column to job_reservation_units...")
+            cursor.execute("ALTER TABLE job_reservation_units ADD COLUMN unit_end_tbd BOOLEAN DEFAULT 0")
+
+        if 'notes' not in unit_cols:
+            print("Adding notes column to job_reservation_units...")
+            cursor.execute("ALTER TABLE job_reservation_units ADD COLUMN notes TEXT")
+
+        conn.commit()
+        print("Migration completed successfully!")
+
+    except Exception as e:
+        print(f"Migration failed: {e}")
+        conn.rollback()
+        raise
+    finally:
+        conn.close()
+
+
+if __name__ == "__main__":
+    # Default to dev database
+    db_path = "./data-dev/seismo_fleet.db"
+
+    if len(sys.argv) > 1:
+        db_path = sys.argv[1]
+
+    if not Path(db_path).exists():
+        print(f"Database not found: {db_path}")
+        sys.exit(1)
+
+    migrate(db_path)
diff --git a/backend/migrate_fix_end_date_nullable.py b/backend/migrate_fix_end_date_nullable.py
new file mode 100644
index 0000000..60aec41
--- /dev/null
+++ b/backend/migrate_fix_end_date_nullable.py
@@ -0,0 +1,105 @@
+"""
+Migration: Make job_reservations.end_date nullable for TBD support
+
+SQLite doesn't support ALTER COLUMN, so we need to:
+1. Create a new table with the correct schema
+2. Copy data
+3. Drop old table
+4. Rename new table
+"""
+
+import sqlite3
+import sys
+from pathlib import Path
+
+def migrate(db_path: str):
+    """Run the migration."""
+    print(f"Migrating database: {db_path}")
+
+    conn = sqlite3.connect(db_path)
+    cursor = conn.cursor()
+
+    try:
+        # Check if job_reservations table exists
+        cursor.execute("SELECT name FROM sqlite_master WHERE type='table' AND name='job_reservations'")
+        if not cursor.fetchone():
+            print("job_reservations table does not exist. Skipping migration.")
+            return
+
+        # Check current schema
+        cursor.execute("PRAGMA table_info(job_reservations)")
+        columns = cursor.fetchall()
+        col_info = {row[1]: row for row in columns}
+
+        # Check if end_date is already nullable (notnull=0)
+        if 'end_date' in col_info and col_info['end_date'][3] == 0:
+            print("end_date is already nullable. Skipping table recreation.")
+            return
+
+        print("Recreating job_reservations table with nullable end_date...")
+
+        # Create new table with correct schema
+        cursor.execute("""
+            CREATE TABLE job_reservations_new (
+                id TEXT PRIMARY KEY,
+                name TEXT NOT NULL,
+                project_id TEXT,
+                start_date DATE NOT NULL,
+                end_date DATE,
+                estimated_end_date DATE,
+                end_date_tbd BOOLEAN DEFAULT 0,
+                assignment_type TEXT NOT NULL DEFAULT 'quantity',
+                device_type TEXT DEFAULT 'seismograph',
+                quantity_needed INTEGER,
+                notes TEXT,
+                color TEXT DEFAULT '#3B82F6',
+                created_at DATETIME,
+                updated_at DATETIME
+            )
+        """)
+
+        # Copy existing data
+        cursor.execute("""
+            INSERT INTO job_reservations_new
+            SELECT
+                id, name, project_id, start_date, end_date,
+                COALESCE(estimated_end_date, NULL) as estimated_end_date,
+                COALESCE(end_date_tbd, 0) as end_date_tbd,
+                assignment_type, device_type, quantity_needed, notes, color,
+                created_at, updated_at
+            FROM job_reservations
+        """)
+
+        # Drop old table
+        cursor.execute("DROP TABLE job_reservations")
+
+        # Rename new table
+        cursor.execute("ALTER TABLE job_reservations_new RENAME TO job_reservations")
+
+        # Recreate index
+        cursor.execute("CREATE INDEX IF NOT EXISTS ix_job_reservations_id ON job_reservations (id)")
+        cursor.execute("CREATE INDEX IF NOT EXISTS ix_job_reservations_project_id ON job_reservations (project_id)")
+
+        conn.commit()
+        print("Migration completed successfully!")
+
+    except Exception as e:
+        print(f"Migration failed: {e}")
+        conn.rollback()
+        raise
+    finally:
+        conn.close()
+
+
+if __name__ == "__main__":
+    # Default to dev database
+    db_path = "./data-dev/seismo_fleet.db"
+
+    if len(sys.argv) > 1:
+        db_path = sys.argv[1]
+
+    if not Path(db_path).exists():
+        print(f"Database not found: {db_path}")
+        sys.exit(1)
+
+    migrate(db_path)
diff --git a/backend/models.py b/backend/models.py
index 41a9c4c..b6d2c6f 100644
--- a/backend/models.py
+++ b/backend/models.py
@@ -402,3 +402,72 @@ class Alert(Base):
 
     created_at = Column(DateTime, default=datetime.utcnow)
     expires_at = Column(DateTime, nullable=True)  # Auto-dismiss after this time
+
+
+# ============================================================================
+# Fleet Calendar & Job Reservations
+# ============================================================================
+
+class JobReservation(Base):
+    """
+    Job reservations: reserve units for future jobs/projects.
+
+    Supports two assignment modes:
+    - "specific": Pick exact units (SN-001, SN-002, etc.)
+    - "quantity": Reserve a number of units (e.g., "need 8 seismographs")
+
+    Used by the Fleet Calendar to visualize unit availability over time.
+    """
+    __tablename__ = "job_reservations"
+
+    id = Column(String, primary_key=True, index=True)  # UUID
+    name = Column(String, nullable=False)  # "Job A - March deployment"
+    project_id = Column(String, nullable=True, index=True)  # Optional FK to Project
+
+    # Date range for the reservation
+    start_date = Column(Date, nullable=False)
+    end_date = Column(Date, nullable=True)  # Nullable = TBD / ongoing
+    estimated_end_date = Column(Date, nullable=True)  # For planning when end is TBD
+    end_date_tbd = Column(Boolean, default=False)  # True = end date unknown
+
+    # Assignment type: "specific" or "quantity"
+    assignment_type = Column(String, nullable=False, default="quantity")
+
+    # For quantity reservations
+    device_type = Column(String, default="seismograph")  # seismograph | slm
+    quantity_needed = Column(Integer, nullable=True)  # e.g., 8 units
+
+    # Metadata
+    notes = Column(Text, nullable=True)
+    color = Column(String, default="#3B82F6")  # For calendar display (blue default)
+
+    created_at = Column(DateTime, default=datetime.utcnow)
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
+
+
+class JobReservationUnit(Base):
+    """
+    Links specific units to job reservations.
+
+    Used when:
+    - assignment_type="specific": Units are directly assigned
+    - assignment_type="quantity": Units can be filled in later
+
+    Supports unit swaps: same reservation can have multiple units with
+    different date ranges (e.g., BE17353 Feb-Jun, then BE18438 Jun-Nov).
+    """
+    __tablename__ = "job_reservation_units"
+
+    id = Column(String, primary_key=True, index=True)  # UUID
+    reservation_id = Column(String, nullable=False, index=True)  # FK to JobReservation
+    unit_id = Column(String, nullable=False, index=True)  # FK to RosterUnit
+
+    # Unit-specific date range (for swaps) - defaults to reservation dates if null
+    unit_start_date = Column(Date, nullable=True)  # When this specific unit starts
+    unit_end_date = Column(Date, nullable=True)  # When this unit ends (swap out date)
+    unit_end_tbd = Column(Boolean, default=False)  # True = end unknown (until cal expires or job ends)
+
+    # Track how this assignment was made
+    assignment_source = Column(String, default="specific")  # "specific" | "filled" | "swap"
+    assigned_at = Column(DateTime, default=datetime.utcnow)
+    notes = Column(Text, nullable=True)  # "Replacing BE17353" etc.
diff --git a/backend/routers/fleet_calendar.py b/backend/routers/fleet_calendar.py
new file mode 100644
index 0000000..170c7e0
--- /dev/null
+++ b/backend/routers/fleet_calendar.py
@@ -0,0 +1,610 @@
+"""
+Fleet Calendar Router
+
+API endpoints for the Fleet Calendar feature:
+- Calendar page and data
+- Job reservation CRUD
+- Unit assignment management
+- Availability checking
+"""
+
+from fastapi import APIRouter, Request, Depends, HTTPException, Query
+from fastapi.responses import HTMLResponse, JSONResponse
+from sqlalchemy.orm import Session
+from datetime import datetime, date, timedelta
+from typing import Optional, List
+import uuid
+import logging
+
+from backend.database import get_db
+from backend.models import (
+    RosterUnit, JobReservation, JobReservationUnit,
+    UserPreferences, Project
+)
+from backend.templates_config import templates
+from backend.services.fleet_calendar_service import (
+    get_day_summary,
+    get_calendar_year_data,
+    get_rolling_calendar_data,
+    check_calibration_conflicts,
+    get_available_units_for_period,
+    get_calibration_status
+)
+
+router = APIRouter(tags=["fleet-calendar"])
+logger = logging.getLogger(__name__)
+
+
+# ============================================================================
+# Calendar Page
+# ============================================================================
+
+@router.get("/fleet-calendar", response_class=HTMLResponse)
+async def fleet_calendar_page(
+    request: Request,
+    year: Optional[int] = None,
+    month: Optional[int] = None,
+    device_type: str = "seismograph",
+    db: Session = Depends(get_db)
+):
+    """Main Fleet Calendar page with rolling 12-month view."""
+    today = date.today()
+
+    # Default to current month as the start
+    if year is None:
+        year = today.year
+    if month is None:
+        month = today.month
+
+    # Get calendar data for 12 months starting from year/month
+    calendar_data = get_rolling_calendar_data(db, year, month, device_type)
+
+    # Get projects for the reservation form dropdown
+    projects = db.query(Project).filter(
+        Project.status == "active"
+    ).order_by(Project.name).all()
+
+    # Calculate prev/next month navigation
+    prev_year, prev_month = (year - 1, 12) if month == 1 else (year, month - 1)
+    next_year, next_month = (year + 1, 1) if month == 12 else (year, month + 1)
+
+    return templates.TemplateResponse(
+        "fleet_calendar.html",
+        {
+            "request": request,
+            "start_year": year,
+            "start_month": month,
+            "prev_year": prev_year,
+            "prev_month": prev_month,
+            "next_year": next_year,
+            "next_month": next_month,
+            "device_type": device_type,
+            "calendar_data": calendar_data,
+            "projects": projects,
+            "today": today.isoformat()
+        }
+    )
+
+
+# ============================================================================
+# Calendar Data API
+# ============================================================================
+
+@router.get("/api/fleet-calendar/data", response_class=JSONResponse)
+async def get_calendar_data(
+    year: int,
+    device_type: str = "seismograph",
+    db: Session = Depends(get_db)
+):
+    """Get calendar data for a specific year."""
+    return get_calendar_year_data(db, year, device_type)
+
+
+@router.get("/api/fleet-calendar/day/{date_str}", response_class=HTMLResponse)
+async def get_day_detail(
+    request: Request,
+    date_str: str,
+    device_type: str = "seismograph",
+    db: Session = Depends(get_db)
+):
+    """Get detailed view for a specific day (HTMX partial)."""
+    try:
+        check_date = date.fromisoformat(date_str)
+    except ValueError:
+        raise HTTPException(status_code=400, detail="Invalid date format. Use YYYY-MM-DD")
+
+    day_data = get_day_summary(db, check_date, device_type)
+
+    # Get projects for display names
+    projects = {p.id: p for p in db.query(Project).all()}
+
+    return templates.TemplateResponse(
+        "partials/fleet_calendar/day_detail.html",
+        {
+            "request": request,
+            "day_data": day_data,
+            "date_str": date_str,
+            "date_display": check_date.strftime("%B %d, %Y"),
+            "device_type": device_type,
+            "projects": projects
+        }
+    )
+
+
+# ============================================================================
+# Reservation CRUD
+# ============================================================================
+
+@router.post("/api/fleet-calendar/reservations", response_class=JSONResponse)
+async def create_reservation(
+    request: Request,
+    db: Session = Depends(get_db)
+):
+    """Create a new job reservation."""
+    data = await request.json()
+
+    # Validate required fields
+    required = ["name", "start_date", "assignment_type"]
+    for field in required:
+        if field not in data:
+            raise HTTPException(status_code=400, detail=f"Missing required field: {field}")
+
+    # Need either end_date or end_date_tbd
+    end_date_tbd = data.get("end_date_tbd", False)
+    if not end_date_tbd and not data.get("end_date"):
+        raise HTTPException(status_code=400, detail="End date is required unless marked as TBD")
+
+    try:
+        start_date = date.fromisoformat(data["start_date"])
+        end_date = date.fromisoformat(data["end_date"]) if data.get("end_date") else None
+        estimated_end_date = date.fromisoformat(data["estimated_end_date"]) if data.get("estimated_end_date") else None
+    except ValueError:
+        raise HTTPException(status_code=400, detail="Invalid date format. Use YYYY-MM-DD")
+
+    if end_date and end_date < start_date:
+        raise HTTPException(status_code=400, detail="End date must be after start date")
+
+    if estimated_end_date and estimated_end_date < start_date:
+        raise HTTPException(status_code=400, detail="Estimated end date must be after start date")
+
+    reservation = JobReservation(
+        id=str(uuid.uuid4()),
+        name=data["name"],
+        project_id=data.get("project_id"),
+        start_date=start_date,
+        end_date=end_date,
+        estimated_end_date=estimated_end_date,
+        end_date_tbd=end_date_tbd,
+        assignment_type=data["assignment_type"],
+        device_type=data.get("device_type", "seismograph"),
+        quantity_needed=data.get("quantity_needed"),
+        notes=data.get("notes"),
+        color=data.get("color", "#3B82F6")
+    )
+
+    db.add(reservation)
+
+    # If specific units were provided, assign them
+    if data.get("unit_ids") and data["assignment_type"] == "specific":
+        for unit_id in data["unit_ids"]:
+            assignment = JobReservationUnit(
+                id=str(uuid.uuid4()),
+                reservation_id=reservation.id,
+                unit_id=unit_id,
+                assignment_source="specific"
+            )
+            db.add(assignment)
+
+    db.commit()
+
+    logger.info(f"Created reservation: {reservation.name} ({reservation.id})")
+
+    return {
+        "success": True,
+        "reservation_id": reservation.id,
+        "message": f"Created reservation: {reservation.name}"
+    }
+
+
+@router.get("/api/fleet-calendar/reservations/{reservation_id}", response_class=JSONResponse)
+async def get_reservation(
+    reservation_id: str,
+    db: Session = Depends(get_db)
+):
+    """Get a specific reservation with its assigned units."""
+    reservation = db.query(JobReservation).filter_by(id=reservation_id).first()
+    if not reservation:
+        raise HTTPException(status_code=404, detail="Reservation not found")
+
+    # Get assigned units
+    assignments = db.query(JobReservationUnit).filter_by(
+        reservation_id=reservation_id
+    ).all()
+
+    unit_ids = [a.unit_id for a in assignments]
+    units = db.query(RosterUnit).filter(RosterUnit.id.in_(unit_ids)).all() if unit_ids else []
+
+    return {
+        "id": reservation.id,
+        "name": reservation.name,
+        "project_id": reservation.project_id,
+        "start_date": reservation.start_date.isoformat(),
+        "end_date": reservation.end_date.isoformat() if reservation.end_date else None,
+        "estimated_end_date": reservation.estimated_end_date.isoformat() if reservation.estimated_end_date else None,
+        "end_date_tbd": reservation.end_date_tbd,
+        "assignment_type": reservation.assignment_type,
+        "device_type": reservation.device_type,
+        "quantity_needed": reservation.quantity_needed,
+        "notes": reservation.notes,
+        "color": reservation.color,
+        "assigned_units": [
+            {
+                "id": u.id,
+                "last_calibrated": u.last_calibrated.isoformat() if u.last_calibrated else None,
+                "deployed": u.deployed
+            }
+            for u in units
+        ]
+    }
+
+
+@router.put("/api/fleet-calendar/reservations/{reservation_id}", response_class=JSONResponse)
+async def update_reservation(
+    reservation_id: str,
+    request: Request,
+    db: Session = Depends(get_db)
+):
+    """Update an existing reservation."""
+    reservation = db.query(JobReservation).filter_by(id=reservation_id).first()
+    if not reservation:
+        raise HTTPException(status_code=404, detail="Reservation not found")
+
+    data = await request.json()
+
+    # Update fields if provided
+    if "name" in data:
+        reservation.name = data["name"]
+    if "project_id" in data:
+        reservation.project_id = data["project_id"]
+    if "start_date" in data:
+        reservation.start_date = date.fromisoformat(data["start_date"])
+    if "end_date" in data:
+        reservation.end_date = date.fromisoformat(data["end_date"]) if data["end_date"] else None
+    if "estimated_end_date" in data:
+        reservation.estimated_end_date = date.fromisoformat(data["estimated_end_date"]) if data["estimated_end_date"] else None
+    if "end_date_tbd" in data:
+        reservation.end_date_tbd = data["end_date_tbd"]
+    if "assignment_type" in data:
+        reservation.assignment_type = data["assignment_type"]
+    if "quantity_needed" in data:
+        reservation.quantity_needed = data["quantity_needed"]
+    if "notes" in data:
+        reservation.notes = data["notes"]
+    if "color" in data:
+        reservation.color = data["color"]
+
+    reservation.updated_at = datetime.utcnow()
+
+    db.commit()
+
+    logger.info(f"Updated reservation: {reservation.name} ({reservation.id})")
+
+    return {
+        "success": True,
+        "message": f"Updated reservation: {reservation.name}"
+    }
+
+
+@router.delete("/api/fleet-calendar/reservations/{reservation_id}", response_class=JSONResponse)
+async def delete_reservation(
+    reservation_id: str,
+    db: Session = Depends(get_db)
+):
+    """Delete a reservation and its unit assignments."""
+    reservation = db.query(JobReservation).filter_by(id=reservation_id).first()
+    if not reservation:
+        raise HTTPException(status_code=404, detail="Reservation not found")
+
+    # Delete unit assignments first
+    db.query(JobReservationUnit).filter_by(reservation_id=reservation_id).delete()
+
+    # Delete the reservation
+    db.delete(reservation)
+    db.commit()
+
+    logger.info(f"Deleted reservation: {reservation.name} ({reservation_id})")
+
+    return {
+        "success": True,
+        "message": "Reservation deleted"
+    }
+
+
+# ============================================================================
+# Unit Assignment
+# ============================================================================
+
+@router.post("/api/fleet-calendar/reservations/{reservation_id}/assign-units", response_class=JSONResponse)
+async def assign_units_to_reservation(
+    reservation_id: str,
+    request: Request,
+    db: Session = Depends(get_db)
+):
+    """Assign specific units to a reservation."""
+    reservation = db.query(JobReservation).filter_by(id=reservation_id).first()
+    if not reservation:
+        raise HTTPException(status_code=404, detail="Reservation not found")
+
+    data = await request.json()
+    unit_ids = data.get("unit_ids", [])
+
+    if not unit_ids:
+        raise HTTPException(status_code=400, detail="No units specified")
+
+    # Verify units exist
+    units = db.query(RosterUnit).filter(RosterUnit.id.in_(unit_ids)).all()
+    found_ids = {u.id for u in units}
+    missing = set(unit_ids) - found_ids
+    if missing:
+        raise HTTPException(status_code=404, detail=f"Units not found: {', '.join(missing)}")
+
+    # Check for conflicts (already assigned to overlapping reservations)
+    conflicts = []
+    for unit_id in unit_ids:
+        # Check if unit is already assigned to this reservation
+        existing = db.query(JobReservationUnit).filter_by(
+            reservation_id=reservation_id,
+            unit_id=unit_id
+        ).first()
+        if existing:
+            continue  # Already assigned, skip
+
+        # Check overlapping reservations
+        overlapping = db.query(JobReservation).join(
+            JobReservationUnit, JobReservation.id == JobReservationUnit.reservation_id
+        ).filter(
+            JobReservationUnit.unit_id == unit_id,
+            JobReservation.id != reservation_id,
+            JobReservation.start_date <= reservation.end_date,
+            JobReservation.end_date >= reservation.start_date
+        ).first()
+
+        if overlapping:
+            conflicts.append({
+                "unit_id": unit_id,
+                "conflict_reservation": overlapping.name,
+                "conflict_dates": f"{overlapping.start_date} - {overlapping.end_date}"
+            })
+            continue
+
+        # Add assignment
+        assignment = JobReservationUnit(
+            id=str(uuid.uuid4()),
+            reservation_id=reservation_id,
+            unit_id=unit_id,
+            assignment_source="filled" if reservation.assignment_type == "quantity" else "specific"
+        )
+        db.add(assignment)
+
+    db.commit()
+
+    # Check for calibration conflicts
+    cal_conflicts = check_calibration_conflicts(db, reservation_id)
+
+    assigned_count = db.query(JobReservationUnit).filter_by(
+        reservation_id=reservation_id
+    ).count()
+
+    return {
+        "success": True,
+        "assigned_count": assigned_count,
+        "conflicts": conflicts,
+        "calibration_warnings": cal_conflicts,
+        "message": f"Assigned {len(unit_ids) - len(conflicts)} units"
+    }
+
+
+@router.delete("/api/fleet-calendar/reservations/{reservation_id}/units/{unit_id}", response_class=JSONResponse)
+async def remove_unit_from_reservation(
+    reservation_id: str,
+    unit_id: str,
+    db: Session = Depends(get_db)
+):
+    """Remove a unit from a reservation."""
+    assignment = db.query(JobReservationUnit).filter_by(
+        reservation_id=reservation_id,
+        unit_id=unit_id
+    ).first()
+
+    if not assignment:
+        raise HTTPException(status_code=404, detail="Unit assignment not found")
+
+    db.delete(assignment)
+    db.commit()
+
+    return {
+        "success": True,
+        "message": f"Removed {unit_id} from reservation"
+    }
+
+
+# ============================================================================
+# Availability & Conflicts
+# ============================================================================
+
+@router.get("/api/fleet-calendar/availability", response_class=JSONResponse)
+async def check_availability(
+    start_date: str,
+    end_date: str,
+    device_type: str = "seismograph",
+    exclude_reservation_id: Optional[str] = None,
+    db: Session = Depends(get_db)
+):
+    """Get units available for a specific date range."""
+    try:
+        start = date.fromisoformat(start_date)
+        end = date.fromisoformat(end_date)
+    except ValueError:
+        raise HTTPException(status_code=400, detail="Invalid date format. Use YYYY-MM-DD")
+
+    available = get_available_units_for_period(
+        db, start, end, device_type, exclude_reservation_id
+    )
+
+    return {
+        "start_date": start_date,
+        "end_date": end_date,
+        "device_type": device_type,
+        "available_units": available,
+        "count": len(available)
+    }
+
+
+@router.get("/api/fleet-calendar/reservations/{reservation_id}/conflicts", response_class=JSONResponse)
+async def get_reservation_conflicts(
+    reservation_id: str,
+    db: Session = Depends(get_db)
+):
+    """Check for calibration conflicts in a reservation."""
+    reservation = db.query(JobReservation).filter_by(id=reservation_id).first()
+    if not reservation:
+        raise HTTPException(status_code=404, detail="Reservation not found")
+
+    conflicts = check_calibration_conflicts(db, reservation_id)
+
+    return {
+        "reservation_id": reservation_id,
+        "reservation_name": reservation.name,
+        "conflicts": conflicts,
+        "has_conflicts": len(conflicts) > 0
+    }
+
+
+# ============================================================================
+# HTMX Partials
+# ============================================================================
+
+@router.get("/api/fleet-calendar/reservations-list", response_class=HTMLResponse)
+async def get_reservations_list(
+    request: Request,
+    year: Optional[int] = None,
+    month: Optional[int] = None,
+    device_type: str = "seismograph",
+    db: Session = Depends(get_db)
+):
+    """Get list of reservations as HTMX partial."""
+    from sqlalchemy import or_
+
+    today = date.today()
+    if year is None:
+        year = today.year
+    if month is None:
+        month = today.month
+
+    # Calculate 12-month window
+    start_date = date(year, month, 1)
+    # End date is 12 months later
+    end_year = year + ((month + 10) // 12)
+    end_month = ((month + 10) % 12) + 1
+    if end_month == 12:
+        end_date = date(end_year, 12, 31)
+    else:
+        end_date = date(end_year, end_month + 1, 1) - timedelta(days=1)
+
+    # Include TBD reservations that started before window end
+    reservations = db.query(JobReservation).filter(
+        JobReservation.device_type == device_type,
+        JobReservation.start_date <= end_date,
+        or_(
+            JobReservation.end_date >= start_date,
+            JobReservation.end_date == None  # TBD reservations
+        )
+    ).order_by(JobReservation.start_date).all()
+
+    # Get assignment counts
+    reservation_data = []
+    for res in reservations:
+        assigned_count = db.query(JobReservationUnit).filter_by(
+            reservation_id=res.id
+        ).count()
+
+        # Check for calibration conflicts
+        conflicts = check_calibration_conflicts(db, res.id)
+
+        reservation_data.append({
+            "reservation": res,
+            "assigned_count": assigned_count,
+            "has_conflicts": len(conflicts) > 0,
+            "conflict_count": len(conflicts)
+        })
+
+    return templates.TemplateResponse(
+        "partials/fleet_calendar/reservations_list.html",
+        {
+            "request": request,
+            "reservations": reservation_data,
+            "year": year,
+            "device_type": device_type
+        }
+    )
+
+
+@router.get("/api/fleet-calendar/available-units", response_class=HTMLResponse)
+async def get_available_units_partial(
+    request: Request,
+    start_date: str,
+    end_date: str,
+    device_type: str = "seismograph",
+    reservation_id: Optional[str] = None,
+    db: Session = Depends(get_db)
+):
+    """Get available units as HTMX partial for the assignment modal."""
+    try:
+        start = date.fromisoformat(start_date)
+        end = date.fromisoformat(end_date)
+    except ValueError:
+        raise HTTPException(status_code=400, detail="Invalid date format")
+
+    available = get_available_units_for_period(
+        db, start, end, device_type, reservation_id
+    )
+
+    return templates.TemplateResponse(
+        "partials/fleet_calendar/available_units.html",
+        {
+            "request": request,
+            "units": available,
+            "start_date": start_date,
+            "end_date": end_date,
+            "device_type": device_type,
+            "reservation_id": reservation_id
+        }
+    )
+
+
+@router.get("/api/fleet-calendar/month/{year}/{month}", response_class=HTMLResponse)
+async def get_month_partial(
+    request: Request,
+    year: int,
+    month: int,
+    device_type: str = "seismograph",
+    db: Session = Depends(get_db)
+):
+    """Get a single month calendar as HTMX partial."""
+    calendar_data = get_calendar_year_data(db, year, device_type)
+    month_data = calendar_data["months"].get(month)
+
+    if not month_data:
+        raise HTTPException(status_code=404, detail="Invalid month")
+
+    return templates.TemplateResponse(
+        "partials/fleet_calendar/month_grid.html",
+        {
+            "request": request,
+            "year": year,
+            "month": month,
+            "month_data": month_data,
+            "device_type": device_type,
+            "today": date.today().isoformat()
+        }
+    )
diff --git a/backend/routers/roster_edit.py b/backend/routers/roster_edit.py
index 0f939b7..9bb62b1 100644
--- a/backend/routers/roster_edit.py
+++ b/backend/routers/roster_edit.py
@@ -1,7 +1,7 @@
 from fastapi import APIRouter, Depends, HTTPException, Form, UploadFile, File, Request, Query
 from fastapi.exceptions import RequestValidationError
 from sqlalchemy.orm import Session
-from datetime import datetime, date
+from datetime import datetime, date, timedelta
 import csv
 import io
 import logging
@@ -185,8 +185,13 @@ async def add_roster_unit(
         except ValueError:
             raise HTTPException(status_code=400, detail="Invalid last_calibrated date format. Use YYYY-MM-DD")
 
+    # Auto-calculate next_calibration_due (1 year from last_calibrated)
+    # This is calculated internally but not shown to user (they just see last_calibrated)
     next_cal_date = None
-    if next_calibration_due:
+    if last_cal_date:
+        next_cal_date = last_cal_date + timedelta(days=365)
+    elif next_calibration_due:
+        # Fallback: allow explicit setting if no last_calibrated
         try:
             next_cal_date = datetime.strptime(next_calibration_due, "%Y-%m-%d").date()
         except ValueError:
@@ -517,8 +522,13 @@ async def edit_roster_unit(
         except ValueError:
             raise HTTPException(status_code=400, detail="Invalid last_calibrated date format. Use YYYY-MM-DD")
 
+    # Auto-calculate next_calibration_due (1 year from last_calibrated)
+    # This is calculated internally but not shown to user (they just see last_calibrated)
     next_cal_date = None
-    if next_calibration_due:
+    if last_cal_date:
+        next_cal_date = last_cal_date + timedelta(days=365)
+    elif next_calibration_due:
+        # Fallback: allow explicit setting if no last_calibrated
         try:
             next_cal_date = datetime.strptime(next_calibration_due, "%Y-%m-%d").date()
         except ValueError:
@@ -995,8 +1005,13 @@ async def import_csv(
 
                 # Seismograph-specific fields
                 if row.get('last_calibrated'):
-                    existing_unit.last_calibrated = _parse_date(row.get('last_calibrated'))
-                if row.get('next_calibration_due'):
+                    last_cal = _parse_date(row.get('last_calibrated'))
+                    existing_unit.last_calibrated = last_cal
+                    # Auto-calculate next_calibration_due (1 year from last_calibrated)
+                    if last_cal:
+                                        existing_unit.next_calibration_due = last_cal + timedelta(days=365)
+                elif row.get('next_calibration_due'):
+                    # Only use explicit next_calibration_due if no last_calibrated
                     existing_unit.next_calibration_due = _parse_date(row.get('next_calibration_due'))
                 if row.get('deployed_with_modem_id'):
                     existing_unit.deployed_with_modem_id = _get_csv_value(row, 'deployed_with_modem_id')
@@ -1046,9 +1061,13 @@ async def import_csv(
                     address=_get_csv_value(row, 'address'),
                     coordinates=_get_csv_value(row, 'coordinates'),
                     last_updated=datetime.utcnow(),
-                    # Seismograph fields
+                    # Seismograph fields - auto-calc next_calibration_due from last_calibrated
                     last_calibrated=_parse_date(row.get('last_calibrated', '')),
-                    next_calibration_due=_parse_date(row.get('next_calibration_due', '')),
+                    next_calibration_due=(
+                        _parse_date(row.get('last_calibrated', '')) + timedelta(days=365)
+                        if _parse_date(row.get('last_calibrated', ''))
+                        else _parse_date(row.get('next_calibration_due', ''))
+                    ),
                     deployed_with_modem_id=_get_csv_value(row, 'deployed_with_modem_id'),
                     # Modem fields
                     ip_address=_get_csv_value(row, 'ip_address'),
diff --git a/backend/services/fleet_calendar_service.py b/backend/services/fleet_calendar_service.py
new file mode 100644
index 0000000..33b5ce7
--- /dev/null
+++ b/backend/services/fleet_calendar_service.py
@@ -0,0 +1,668 @@
+"""
+Fleet Calendar Service
+
+Business logic for:
+- Calculating unit availability on any given date
+- Calibration status tracking (valid, expiring soon, expired)
+- Job reservation management
+- Conflict detection (calibration expires mid-job)
+"""
+
+from datetime import date, datetime, timedelta
+from typing import Dict, List, Optional, Tuple
+from sqlalchemy.orm import Session
+from sqlalchemy import and_, or_
+
+from backend.models import (
+    RosterUnit, JobReservation, JobReservationUnit,
+    UserPreferences, Project
+)
+
+
+def get_calibration_status(
+    unit: RosterUnit,
+    check_date: date,
+    warning_days: int = 30
+) -> str:
+    """
+    Determine calibration status for a unit on a specific date.
+
+    Returns:
+        "valid" - Calibration is good on this date
+        "expiring_soon" - Within warning_days of expiry
+        "expired" - Calibration has expired
+        "needs_calibration" - No calibration date set
+    """
+    if not unit.last_calibrated:
+        return "needs_calibration"
+
+    # Calculate expiry date (1 year from last calibration)
+    expiry_date = unit.last_calibrated + timedelta(days=365)
+
+    if check_date >= expiry_date:
+        return "expired"
+    elif check_date >= expiry_date - timedelta(days=warning_days):
+        return "expiring_soon"
+    else:
+        return "valid"
+
+
+def get_unit_reservations_on_date(
+    db: Session,
+    unit_id: str,
+    check_date: date
+) -> List[JobReservation]:
+    """Get all reservations that include this unit on the given date."""
+
+    # Get reservation IDs that have this unit assigned
+    assigned_reservation_ids = db.query(JobReservationUnit.reservation_id).filter(
+        JobReservationUnit.unit_id == unit_id
+    ).subquery()
+
+    # Get reservations that:
+    # 1. Have this unit assigned AND date is within range
+    reservations = db.query(JobReservation).filter(
+        JobReservation.id.in_(assigned_reservation_ids),
+        JobReservation.start_date <= check_date,
+        JobReservation.end_date >= check_date
+    ).all()
+
+    return reservations
+
+
+def is_unit_available_on_date(
+    db: Session,
+    unit: RosterUnit,
+    check_date: date,
+    warning_days: int = 30
+) -> Tuple[bool, str, Optional[str]]:
+    """
+    Check if a unit is available on a specific date.
+
+    Returns:
+        (is_available, status, reservation_name)
+        - is_available: True if unit can be assigned to new work
+        - status: "available", "reserved", "expired", "retired", "needs_calibration"
+        - reservation_name: Name of blocking reservation (if any)
+    """
+    # Check if retired
+    if unit.retired:
+        return False, "retired", None
+
+    # Check calibration status
+    cal_status = get_calibration_status(unit, check_date, warning_days)
+    if cal_status == "expired":
+        return False, "expired", None
+    if cal_status == "needs_calibration":
+        return False, "needs_calibration", None
+
+    # Check if already reserved
+    reservations = get_unit_reservations_on_date(db, unit.id, check_date)
+    if reservations:
+        return False, "reserved", reservations[0].name
+
+    # Unit is available (even if expiring soon - that's just a warning)
+    return True, "available", None
+
+
+def get_day_summary(
+    db: Session,
+    check_date: date,
+    device_type: str = "seismograph"
+) -> Dict:
+    """
+    Get a complete summary of fleet status for a specific day.
+
+    Returns dict with:
+        - available_units: List of available unit IDs with calibration info
+        - reserved_units: List of reserved unit IDs with reservation info
+        - expired_units: List of units with expired calibration
+        - expiring_soon_units: List of units expiring within warning period
+        - reservations: List of active reservations on this date
+        - counts: Summary counts
+    """
+    # Get user preferences for warning days
+    prefs = db.query(UserPreferences).filter_by(id=1).first()
+    warning_days = prefs.calibration_warning_days if prefs else 30
+
+    # Get all non-retired units of the specified device type
+    units = db.query(RosterUnit).filter(
+        RosterUnit.device_type == device_type,
+        RosterUnit.retired == False
+    ).all()
+
+    available_units = []
+    reserved_units = []
+    expired_units = []
+    expiring_soon_units = []
+    needs_calibration_units = []
+    cal_expiring_today = []  # Units whose calibration expires ON this day
+
+    for unit in units:
+        is_avail, status, reservation_name = is_unit_available_on_date(
+            db, unit, check_date, warning_days
+        )
+
+        cal_status = get_calibration_status(unit, check_date, warning_days)
+        expiry_date = None
+        if unit.last_calibrated:
+            expiry_date = (unit.last_calibrated + timedelta(days=365)).isoformat()
+
+        unit_info = {
+            "id": unit.id,
+            "last_calibrated": unit.last_calibrated.isoformat() if unit.last_calibrated else None,
+            "expiry_date": expiry_date,
+            "calibration_status": cal_status,
+            "deployed": unit.deployed,
+            "note": unit.note or ""
+        }
+
+        # Check if calibration expires ON this specific day
+        if unit.last_calibrated:
+            unit_expiry_date = unit.last_calibrated + timedelta(days=365)
+            if unit_expiry_date == check_date:
+                cal_expiring_today.append(unit_info)
+
+        if status == "available":
+            available_units.append(unit_info)
+            if cal_status == "expiring_soon":
+                expiring_soon_units.append(unit_info)
+        elif status == "reserved":
+            unit_info["reservation_name"] = reservation_name
+            reserved_units.append(unit_info)
+            if cal_status == "expiring_soon":
+                expiring_soon_units.append(unit_info)
+        elif status == "expired":
+            expired_units.append(unit_info)
+        elif status == "needs_calibration":
+            needs_calibration_units.append(unit_info)
+
+    # Get active reservations on this date
+    reservations = db.query(JobReservation).filter(
+        JobReservation.device_type == device_type,
+        JobReservation.start_date <= check_date,
+        JobReservation.end_date >= check_date
+    ).all()
+
+    reservation_list = []
+    for res in reservations:
+        # Count assigned units for this reservation
+        assigned_count = db.query(JobReservationUnit).filter(
+            JobReservationUnit.reservation_id == res.id
+        ).count()
+
+        reservation_list.append({
+            "id": res.id,
+            "name": res.name,
+            "start_date": res.start_date.isoformat(),
+            "end_date": res.end_date.isoformat(),
+            "assignment_type": res.assignment_type,
+            "quantity_needed": res.quantity_needed,
+            "assigned_count": assigned_count,
+            "color": res.color,
+            "project_id": res.project_id
+        })
+
+    return {
+        "date": check_date.isoformat(),
+        "device_type": device_type,
+        "available_units": available_units,
+        "reserved_units": reserved_units,
+        "expired_units": expired_units,
+        "expiring_soon_units": expiring_soon_units,
+        "needs_calibration_units": needs_calibration_units,
+        "cal_expiring_today": cal_expiring_today,
+        "reservations": reservation_list,
+        "counts": {
+            "available": len(available_units),
+            "reserved": len(reserved_units),
+            "expired": len(expired_units),
+            "expiring_soon": len(expiring_soon_units),
+            "needs_calibration": len(needs_calibration_units),
+            "cal_expiring_today": len(cal_expiring_today),
+            "total": len(units)
+        }
+    }
+
+
+def get_calendar_year_data(
+    db: Session,
+    year: int,
+    device_type: str = "seismograph"
+) -> Dict:
+    """
+    Get calendar data for an entire year.
+
+    For performance, this returns summary counts per day rather than
+    full unit lists. Use get_day_summary() for detailed day data.
+    """
+    # Get user preferences
+    prefs = db.query(UserPreferences).filter_by(id=1).first()
+    warning_days = prefs.calibration_warning_days if prefs else 30
+
+    # Get all units
+    units = db.query(RosterUnit).filter(
+        RosterUnit.device_type == device_type,
+        RosterUnit.retired == False
+    ).all()
+
+    # Get all reservations that overlap with this year
+    # Include TBD reservations (end_date is null) that started before year end
+    year_start = date(year, 1, 1)
+    year_end = date(year, 12, 31)
+
+    reservations = db.query(JobReservation).filter(
+        JobReservation.device_type == device_type,
+        JobReservation.start_date <= year_end,
+        or_(
+            JobReservation.end_date >= year_start,
+            JobReservation.end_date == None  # TBD reservations
+        )
+    ).all()
+
+    # Get all unit assignments for these reservations
+    reservation_ids = [r.id for r in reservations]
+    assignments = db.query(JobReservationUnit).filter(
+        JobReservationUnit.reservation_id.in_(reservation_ids)
+    ).all() if reservation_ids else []
+
+    # Build a lookup: unit_id -> list of (start_date, end_date, reservation_name)
+    # For TBD reservations, use estimated_end_date if available, or a far future date
+    unit_reservations = {}
+    for res in reservations:
+        res_assignments = [a for a in assignments if a.reservation_id == res.id]
+        for assignment in res_assignments:
+            unit_id = assignment.unit_id
+            # Use unit-specific dates if set, otherwise use reservation dates
+            start_d = assignment.unit_start_date or res.start_date
+            if assignment.unit_end_tbd or (assignment.unit_end_date is None and res.end_date_tbd):
+                # TBD: use estimated date or far future for availability calculation
+                end_d = res.estimated_end_date or date(year + 5, 12, 31)
+            else:
+                end_d = assignment.unit_end_date or res.end_date or date(year + 5, 12, 31)
+
+            if unit_id not in unit_reservations:
+                unit_reservations[unit_id] = []
+            unit_reservations[unit_id].append((start_d, end_d, res.name))
+
+    # Generate data for each month
+    months_data = {}
+
+    for month in range(1, 13):
+        # Get first and last day of month
+        first_day = date(year, month, 1)
+        if month == 12:
+            last_day = date(year, 12, 31)
+        else:
+            last_day = date(year, month + 1, 1) - timedelta(days=1)
+
+        days_data = {}
+        current_day = first_day
+
+        while current_day <= last_day:
+            available = 0
+            reserved = 0
+            expired = 0
+            expiring_soon = 0
+            needs_cal = 0
+            cal_expiring_on_day = 0  # Units whose calibration expires ON this day
+            cal_expired_on_day = 0   # Units whose calibration expired ON this day
+
+            for unit in units:
+                # Check calibration
+                cal_status = get_calibration_status(unit, current_day, warning_days)
+
+                # Check if calibration expires/expired ON this specific day
+                if unit.last_calibrated:
+                    unit_expiry = unit.last_calibrated + timedelta(days=365)
+                    if unit_expiry == current_day:
+                        cal_expiring_on_day += 1
+                    # Check if expired yesterday (first day of being expired)
+                    elif unit_expiry == current_day - timedelta(days=1):
+                        cal_expired_on_day += 1
+
+                if cal_status == "expired":
+                    expired += 1
+                    continue
+                if cal_status == "needs_calibration":
+                    needs_cal += 1
+                    continue
+
+                # Check if reserved
+                is_reserved = False
+                if unit.id in unit_reservations:
+                    for start_d, end_d, _ in unit_reservations[unit.id]:
+                        if start_d <= current_day <= end_d:
+                            is_reserved = True
+                            break
+
+                if is_reserved:
+                    reserved += 1
+                else:
+                    available += 1
+
+                if cal_status == "expiring_soon":
+                    expiring_soon += 1
+
+            days_data[current_day.day] = {
+                "available": available,
+                "reserved": reserved,
+                "expired": expired,
+                "expiring_soon": expiring_soon,
+                "needs_calibration": needs_cal,
+                "cal_expiring_on_day": cal_expiring_on_day,
+                "cal_expired_on_day": cal_expired_on_day
+            }
+
+            current_day += timedelta(days=1)
+
+        months_data[month] = {
+            "name": first_day.strftime("%B"),
+            "short_name": first_day.strftime("%b"),
+            "days": days_data,
+            "first_weekday": first_day.weekday(),  # 0=Monday, 6=Sunday
+            "num_days": last_day.day
+        }
+
+    # Also include reservation summary for the year
+    reservation_list = []
+    for res in reservations:
+        assigned_count = len([a for a in assignments if a.reservation_id == res.id])
+        reservation_list.append({
+            "id": res.id,
+            "name": res.name,
+            "start_date": res.start_date.isoformat(),
+            "end_date": res.end_date.isoformat(),
+            "quantity_needed": res.quantity_needed,
+            "assigned_count": assigned_count,
+            "color": res.color
+        })
+
+    return {
+        "year": year,
+        "device_type": device_type,
+        "months": months_data,
+        "reservations": reservation_list,
+        "total_units": len(units)
+    }
+
+
+def get_rolling_calendar_data(
+    db: Session,
+    start_year: int,
+    start_month: int,
+    device_type: str = "seismograph"
+) -> Dict:
+    """
+    Get calendar data for 12 months starting from a specific month/year.
+
+    This supports the rolling calendar view where users can scroll through
+    months one at a time, viewing any 12-month window.
+    """
+    # Get user preferences
+    prefs = db.query(UserPreferences).filter_by(id=1).first()
+    warning_days = prefs.calibration_warning_days if prefs else 30
+
+    # Get all units
+    units = db.query(RosterUnit).filter(
+        RosterUnit.device_type == device_type,
+        RosterUnit.retired == False
+    ).all()
+
+    # Calculate the date range for 12 months
+    first_date = date(start_year, start_month, 1)
+    # Calculate end date (12 months later)
+    end_year = start_year + 1 if start_month == 1 else start_year
+    end_month = 12 if start_month == 1 else start_month - 1
+    if start_month == 1:
+        end_year = start_year
+        end_month = 12
+    else:
+        # 12 months from start_month means we end at start_month - 1 next year
+        end_year = start_year + 1
+        end_month = start_month - 1
+
+    # Actually, simpler: go 11 months forward from start
+    end_year = start_year + ((start_month + 10) // 12)
+    end_month = ((start_month + 10) % 12) + 1
+    if end_month == 12:
+        last_date = date(end_year, 12, 31)
+    else:
+        last_date = date(end_year, end_month + 1, 1) - timedelta(days=1)
+
+    # Get all reservations that overlap with this 12-month range
+    reservations = db.query(JobReservation).filter(
+        JobReservation.device_type == device_type,
+        JobReservation.start_date <= last_date,
+        or_(
+            JobReservation.end_date >= first_date,
+            JobReservation.end_date == None  # TBD reservations
+        )
+    ).all()
+
+    # Get all unit assignments for these reservations
+    reservation_ids = [r.id for r in reservations]
+    assignments = db.query(JobReservationUnit).filter(
+        JobReservationUnit.reservation_id.in_(reservation_ids)
+    ).all() if reservation_ids else []
+
+    # Build a lookup: unit_id -> list of (start_date, end_date, reservation_name)
+    unit_reservations = {}
+    for res in reservations:
+        res_assignments = [a for a in assignments if a.reservation_id == res.id]
+        for assignment in res_assignments:
+            unit_id = assignment.unit_id
+            start_d = assignment.unit_start_date or res.start_date
+            if assignment.unit_end_tbd or (assignment.unit_end_date is None and res.end_date_tbd):
+                end_d = res.estimated_end_date or date(start_year + 5, 12, 31)
+            else:
+                end_d = assignment.unit_end_date or res.end_date or date(start_year + 5, 12, 31)
+
+            if unit_id not in unit_reservations:
+                unit_reservations[unit_id] = []
+            unit_reservations[unit_id].append((start_d, end_d, res.name))
+
+    # Generate data for each of the 12 months
+    months_data = []
+    current_year = start_year
+    current_month = start_month
+
+    for i in range(12):
+        # Calculate this month's year and month
+        m_year = start_year + ((start_month - 1 + i) // 12)
+        m_month = ((start_month - 1 + i) % 12) + 1
+
+        first_day = date(m_year, m_month, 1)
+        if m_month == 12:
+            last_day = date(m_year, 12, 31)
+        else:
+            last_day = date(m_year, m_month + 1, 1) - timedelta(days=1)
+
+        days_data = {}
+        current_day = first_day
+
+        while current_day <= last_day:
+            available = 0
+            reserved = 0
+            expired = 0
+            expiring_soon = 0
+            needs_cal = 0
+            cal_expiring_on_day = 0
+            cal_expired_on_day = 0
+
+            for unit in units:
+                cal_status = get_calibration_status(unit, current_day, warning_days)
+
+                if unit.last_calibrated:
+                    unit_expiry = unit.last_calibrated + timedelta(days=365)
+                    if unit_expiry == current_day:
+                        cal_expiring_on_day += 1
+                    elif unit_expiry == current_day - timedelta(days=1):
+                        cal_expired_on_day += 1
+
+                if cal_status == "expired":
+                    expired += 1
+                    continue
+                if cal_status == "needs_calibration":
+                    needs_cal += 1
+                    continue
+
+                is_reserved = False
+                if unit.id in unit_reservations:
+                    for start_d, end_d, _ in unit_reservations[unit.id]:
+                        if start_d <= current_day <= end_d:
+                            is_reserved = True
+                            break
+
+                if is_reserved:
+                    reserved += 1
+                else:
+                    available += 1
+
+                if cal_status == "expiring_soon":
+                    expiring_soon += 1
+
+            days_data[current_day.day] = {
+                "available": available,
+                "reserved": reserved,
+                "expired": expired,
+                "expiring_soon": expiring_soon,
+                "needs_calibration": needs_cal,
+                "cal_expiring_on_day": cal_expiring_on_day,
+                "cal_expired_on_day": cal_expired_on_day
+            }
+
+            current_day += timedelta(days=1)
+
+        months_data.append({
+            "year": m_year,
+            "month": m_month,
+            "name": first_day.strftime("%B"),
+            "short_name": first_day.strftime("%b"),
+            "year_short": first_day.strftime("%y"),
+            "days": days_data,
+            "first_weekday": first_day.weekday(),
+            "num_days": last_day.day
+        })
+
+    return {
+        "start_year": start_year,
+        "start_month": start_month,
+        "device_type": device_type,
+        "months": months_data,
+        "total_units": len(units)
+    }
+
+
+def check_calibration_conflicts(
+    db: Session,
+    reservation_id: str
+) -> List[Dict]:
+    """
+    Check if any units assigned to a reservation will have their
+    calibration expire during the reservation period.
+
+    Returns list of conflicts with unit info and expiry date.
+    """
+    reservation = db.query(JobReservation).filter_by(id=reservation_id).first()
+    if not reservation:
+        return []
+
+    # Get assigned units
+    assigned = db.query(JobReservationUnit).filter_by(
+        reservation_id=reservation_id
+    ).all()
+
+    conflicts = []
+    for assignment in assigned:
+        unit = db.query(RosterUnit).filter_by(id=assignment.unit_id).first()
+        if not unit or not unit.last_calibrated:
+            continue
+
+        expiry_date = unit.last_calibrated + timedelta(days=365)
+
+        # Check if expiry falls within reservation period
+        if reservation.start_date < expiry_date <= reservation.end_date:
+            conflicts.append({
+                "unit_id": unit.id,
+                "last_calibrated": unit.last_calibrated.isoformat(),
+                "expiry_date": expiry_date.isoformat(),
+                "reservation_name": reservation.name,
+                "days_into_job": (expiry_date - reservation.start_date).days
+            })
+
+    return conflicts
+
+
+def get_available_units_for_period(
+    db: Session,
+    start_date: date,
+    end_date: date,
+    device_type: str = "seismograph",
+    exclude_reservation_id: Optional[str] = None
+) -> List[Dict]:
+    """
+    Get units that are available for the entire specified period.
+
+    A unit is available if:
+    - Not retired
+    - Calibration is valid through the end date
+    - Not assigned to any other reservation that overlaps the period
+    """
+    prefs = db.query(UserPreferences).filter_by(id=1).first()
+    warning_days = prefs.calibration_warning_days if prefs else 30
+
+    units = db.query(RosterUnit).filter(
+        RosterUnit.device_type == device_type,
+        RosterUnit.retired == False
+    ).all()
+
+    # Get reservations that overlap with this period
+    overlapping_reservations = db.query(JobReservation).filter(
+        JobReservation.device_type == device_type,
+        JobReservation.start_date <= end_date,
+        JobReservation.end_date >= start_date
+    )
+
+    if exclude_reservation_id:
+        overlapping_reservations = overlapping_reservations.filter(
+            JobReservation.id != exclude_reservation_id
+        )
+
+    overlapping_reservations = overlapping_reservations.all()
+
+    # Get all units assigned to overlapping reservations
+    reserved_unit_ids = set()
+    for res in overlapping_reservations:
+        assigned = db.query(JobReservationUnit).filter_by(
+            reservation_id=res.id
+        ).all()
+        for a in assigned:
+            reserved_unit_ids.add(a.unit_id)
+
+    available_units = []
+    for unit in units:
+        # Check if already reserved
+        if unit.id in reserved_unit_ids:
+            continue
+
+        # Check calibration through end of period
+        if not unit.last_calibrated:
+            continue  # Needs calibration
+
+        expiry_date = unit.last_calibrated + timedelta(days=365)
+        if expiry_date <= end_date:
+            continue  # Calibration expires during period
+
+        cal_status = get_calibration_status(unit, end_date, warning_days)
+
+        available_units.append({
+            "id": unit.id,
+            "last_calibrated": unit.last_calibrated.isoformat(),
+            "expiry_date": expiry_date.isoformat(),
+            "calibration_status": cal_status,
+            "deployed": unit.deployed,
+            "note": unit.note or ""
+        })
+
+    return available_units
diff --git a/backend/services/slm_status_sync.py b/backend/services/slm_status_sync.py
index 4ec139b..6666bf7 100644
--- a/backend/services/slm_status_sync.py
+++ b/backend/services/slm_status_sync.py
@@ -70,6 +70,10 @@ async def sync_slm_status_to_emitters() -> Dict[str, Any]:
                         # Convert to naive UTC for consistency with existing code
                         if last_seen.tzinfo:
                             last_seen = last_seen.astimezone(timezone.utc).replace(tzinfo=None)
+                    elif is_reachable:
+                        # Device is reachable but no last_success yet (first poll or just started)
+                        # Use current time so it shows as OK, not Missing
+                        last_seen = datetime.utcnow()
                     else:
                         last_seen = None
 
diff --git a/docker-compose.yml b/docker-compose.yml
index 1de4897..e97357e 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -25,26 +25,28 @@ services:
       start_period: 40s
 
   # --- TERRA-VIEW DEVELOPMENT ---
-  # terra-view-dev:
-  #   build: .
-  #   container_name: terra-view-dev
-  #   ports:
-  #     - "1001:8001"
-  #   volumes:
-  #     - ./data-dev:/app/data
-  #   environment:
-  #     - PYTHONUNBUFFERED=1
-  #     - ENVIRONMENT=development
-  #     - SLMM_BASE_URL=http://slmm:8100
-  #   restart: unless-stopped
-  #   depends_on:
-  #     - slmm
-  #   healthcheck:
-  #     test: ["CMD", "curl", "-f", "http://localhost:8001/health"]
-  #     interval: 30s
-  #     timeout: 10s
-  #     retries: 3
-  #     start_period: 40s
+  terra-view-dev:
+    build: .
+    container_name: terra-view-dev
+    ports:
+      - "1001:8001"
+    volumes:
+      - ./data-dev:/app/data
+    environment:
+      - PYTHONUNBUFFERED=1
+      - ENVIRONMENT=development
+      - SLMM_BASE_URL=http://host.docker.internal:8100
+    restart: unless-stopped
+    depends_on:
+      - slmm
+    extra_hosts:
+      - "host.docker.internal:host-gateway"
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost:8001/health"]
+      interval: 30s
+      timeout: 10s
+      retries: 3
+      start_period: 40s
 
   # --- SLMM (Sound Level Meter Manager) ---
   slmm:
diff --git a/templates/base.html b/templates/base.html
index 8d70e07..8e9b431 100644
--- a/templates/base.html
+++ b/templates/base.html
@@ -151,6 +151,13 @@
                     Projects
                 </a>
 
+                <a href="/fleet-calendar" class="flex items-center px-4 py-3 rounded-lg hover:bg-gray-100 dark:hover:bg-gray-700 {% if request.url.path.startswith('/fleet-calendar') %}bg-gray-100 dark:bg-gray-700{% endif %}">
+                    <svg class="w-5 h-5 mr-3" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                        <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M8 7V3m8 4V3m-9 8h10M5 21h14a2 2 0 002-2V7a2 2 0 00-2-2H5a2 2 0 00-2 2v12a2 2 0 002 2z"></path>
+                    </svg>
+                    Fleet Calendar
+                </a>
+
                 <a href="/settings" class="flex items-center px-4 py-3 rounded-lg hover:bg-gray-100 dark:hover:bg-gray-700 {% if request.url.path == '/settings' %}bg-gray-100 dark:bg-gray-700{% endif %}">
                     <svg class="w-5 h-5 mr-3" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                         <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M10.325 4.317c.426-1.756 2.924-1.756 3.35 0a1.724 1.724 0 002.573 1.066c1.543-.94 3.31.826 2.37 2.37a1.724 1.724 0 001.065 2.572c1.756.426 1.756 2.924 0 3.35a1.724 1.724 0 00-1.066 2.573c.94 1.543-.826 3.31-2.37 2.37a1.724 1.724 0 00-2.572 1.065c-.426 1.756-2.924 1.756-3.35 0a1.724 1.724 0 00-2.573-1.066c-1.543.94-3.31-.826-2.37-2.37a1.724 1.724 0 00-1.065-2.572c-1.756-.426-1.756-2.924 0-3.35a1.724 1.724 0 001.066-2.573c-.94-1.543.826-3.31 2.37-2.37.996.608 2.296.07 2.572-1.065z"></path>
diff --git a/templates/fleet_calendar.html b/templates/fleet_calendar.html
new file mode 100644
index 0000000..09879cf
--- /dev/null
+++ b/templates/fleet_calendar.html
@@ -0,0 +1,811 @@
+{% extends "base.html" %}
+
+{% block title %}Fleet Calendar - Terra-View{% endblock %}
+
+{% block extra_head %}
+<style>
+/* Calendar grid layout */
+.calendar-grid {
+    display: grid;
+    grid-template-columns: repeat(4, 1fr);
+    gap: 1rem;
+}
+
+@media (max-width: 1280px) {
+    .calendar-grid {
+        grid-template-columns: repeat(3, 1fr);
+    }
+}
+
+@media (max-width: 768px) {
+    .calendar-grid {
+        grid-template-columns: repeat(2, 1fr);
+    }
+}
+
+@media (max-width: 480px) {
+    .calendar-grid {
+        grid-template-columns: 1fr;
+    }
+}
+
+/* Month card */
+.month-card {
+    background: white;
+    border-radius: 0.5rem;
+    padding: 0.75rem;
+    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
+}
+
+.dark .month-card {
+    background: rgb(30 41 59);
+}
+
+/* Day grid */
+.day-grid {
+    display: grid;
+    grid-template-columns: repeat(7, 1fr);
+    gap: 2px;
+    font-size: 0.75rem;
+}
+
+.day-header {
+    text-align: center;
+    font-weight: 600;
+    color: #6b7280;
+    padding: 0.25rem 0;
+}
+
+.dark .day-header {
+    color: #9ca3af;
+}
+
+/* Day cell */
+.day-cell {
+    aspect-ratio: 1;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    border-radius: 0.25rem;
+    cursor: pointer;
+    position: relative;
+    transition: all 0.15s ease;
+    font-size: 0.7rem;
+}
+
+.day-cell:hover {
+    transform: scale(1.1);
+    z-index: 10;
+}
+
+.day-cell.today {
+    ring: 2px;
+    ring-color: #f48b1c;
+    font-weight: bold;
+}
+
+/* Default neutral day style */
+.day-cell.neutral {
+    background-color: #f3f4f6;
+    color: #374151;
+}
+
+.dark .day-cell.neutral {
+    background-color: rgba(55, 65, 81, 0.5);
+    color: #d1d5db;
+}
+
+/* Status indicator dot */
+.day-cell .status-dot {
+    position: absolute;
+    top: 2px;
+    right: 2px;
+    width: 5px;
+    height: 5px;
+    border-radius: 50%;
+}
+
+.day-cell .status-dot.expired {
+    background-color: #ef4444;
+}
+
+/* Reservation mode colors - applied dynamically */
+.day-cell.reservation-available {
+    background-color: #dcfce7;
+    color: #166534;
+}
+
+.dark .day-cell.reservation-available {
+    background-color: rgba(34, 197, 94, 0.2);
+    color: #86efac;
+}
+
+.day-cell.reservation-partial {
+    background-color: #fef3c7;
+    color: #92400e;
+}
+
+.dark .day-cell.reservation-partial {
+    background-color: rgba(245, 158, 11, 0.2);
+    color: #fcd34d;
+}
+
+.day-cell.reservation-unavailable {
+    background-color: #fee2e2;
+    color: #991b1b;
+}
+
+.dark .day-cell.reservation-unavailable {
+    background-color: rgba(239, 68, 68, 0.2);
+    color: #fca5a5;
+}
+
+/* Legacy status colors (kept for day detail) */
+.day-cell.some-reserved {
+    background-color: #dbeafe;
+    color: #1e40af;
+}
+
+.dark .day-cell.some-reserved {
+    background-color: rgba(59, 130, 246, 0.2);
+    color: #93c5fd;
+}
+
+.day-cell.empty {
+    background: transparent;
+    cursor: default;
+}
+
+.day-cell.empty:hover {
+    transform: none;
+}
+
+/* Reservation bar */
+.reservation-bar {
+    display: flex;
+    align-items: center;
+    padding: 0.5rem 0.75rem;
+    border-radius: 0.375rem;
+    margin-bottom: 0.5rem;
+    cursor: pointer;
+    transition: opacity 0.15s ease;
+}
+
+.reservation-bar:hover {
+    opacity: 0.8;
+}
+
+/* Slide-over panel */
+.slide-panel {
+    position: fixed;
+    top: 0;
+    right: 0;
+    width: 100%;
+    max-width: 28rem;
+    height: 100vh;
+    background: white;
+    box-shadow: -4px 0 15px rgba(0,0,0,0.1);
+    transform: translateX(100%);
+    transition: transform 0.3s ease;
+    z-index: 50;
+    overflow-y: auto;
+}
+
+.dark .slide-panel {
+    background: rgb(30 41 59);
+}
+
+.slide-panel.open {
+    transform: translateX(0);
+}
+
+.panel-backdrop {
+    position: fixed;
+    inset: 0;
+    background: rgba(0,0,0,0.3);
+    opacity: 0;
+    visibility: hidden;
+    transition: all 0.3s ease;
+    z-index: 40;
+}
+
+.panel-backdrop.open {
+    opacity: 1;
+    visibility: visible;
+}
+</style>
+{% endblock %}
+
+{% block content %}
+<div class="mb-6">
+    <div class="flex flex-col sm:flex-row sm:items-center sm:justify-between gap-4">
+        <div>
+            <h1 class="text-3xl font-bold text-gray-900 dark:text-white">Fleet Calendar</h1>
+            <p class="text-gray-600 dark:text-gray-400 mt-1">Plan unit assignments and track calibrations</p>
+        </div>
+
+    </div>
+</div>
+
+<!-- Summary Stats -->
+<div class="grid grid-cols-2 md:grid-cols-5 gap-4 mb-6">
+    <div class="bg-white dark:bg-slate-800 rounded-lg p-4 shadow">
+        <p class="text-sm text-gray-500 dark:text-gray-400">Total Units</p>
+        <p class="text-2xl font-bold text-gray-900 dark:text-white">{{ calendar_data.total_units }}</p>
+    </div>
+    <div class="bg-green-50 dark:bg-green-900/20 rounded-lg p-4 shadow">
+        <p class="text-sm text-green-600 dark:text-green-400">Available Today</p>
+        <p class="text-2xl font-bold text-green-700 dark:text-green-300" id="available-today">--</p>
+    </div>
+    <div class="bg-blue-50 dark:bg-blue-900/20 rounded-lg p-4 shadow">
+        <p class="text-sm text-blue-600 dark:text-blue-400">Reserved Today</p>
+        <p class="text-2xl font-bold text-blue-700 dark:text-blue-300" id="reserved-today">--</p>
+    </div>
+    <div class="bg-yellow-50 dark:bg-yellow-900/20 rounded-lg p-4 shadow">
+        <p class="text-sm text-yellow-600 dark:text-yellow-400">Expiring Soon</p>
+        <p class="text-2xl font-bold text-yellow-700 dark:text-yellow-300" id="expiring-today">--</p>
+    </div>
+    <div class="bg-red-50 dark:bg-red-900/20 rounded-lg p-4 shadow">
+        <p class="text-sm text-red-600 dark:text-red-400">Cal. Expired</p>
+        <p class="text-2xl font-bold text-red-700 dark:text-red-300" id="expired-today">--</p>
+    </div>
+</div>
+
+<!-- Action Bar -->
+<div class="flex flex-wrap items-center justify-between gap-4 mb-6">
+    <div class="flex items-center gap-4">
+        <!-- Device Type Toggle -->
+        <div class="flex rounded-lg bg-gray-100 dark:bg-gray-700 p-1">
+            <a href="/fleet-calendar?year={{ start_year }}&month={{ start_month }}&device_type=seismograph"
+               class="px-4 py-2 rounded-md text-sm font-medium transition-colors {% if device_type == 'seismograph' %}bg-white dark:bg-slate-600 text-gray-900 dark:text-white shadow{% else %}text-gray-600 dark:text-gray-300 hover:text-gray-900 dark:hover:text-white{% endif %}">
+                Seismographs
+            </a>
+            <a href="/fleet-calendar?year={{ start_year }}&month={{ start_month }}&device_type=slm"
+               class="px-4 py-2 rounded-md text-sm font-medium transition-colors {% if device_type == 'slm' %}bg-white dark:bg-slate-600 text-gray-900 dark:text-white shadow{% else %}text-gray-600 dark:text-gray-300 hover:text-gray-900 dark:hover:text-white{% endif %}">
+                SLMs
+            </a>
+        </div>
+
+        <!-- Legend -->
+        <div class="hidden md:flex items-center gap-4 text-sm" id="main-legend">
+            <span class="flex items-center gap-1">
+                <span class="w-3 h-3 rounded bg-gray-200 dark:bg-gray-600 relative">
+                    <span class="absolute top-0 right-0 w-1.5 h-1.5 rounded-full bg-red-500"></span>
+                </span>
+                Cal expires
+            </span>
+        </div>
+        <!-- Reservation mode legend (hidden by default) -->
+        <div class="hidden md:hidden items-center gap-4 text-sm" id="reservation-legend">
+            <span class="flex items-center gap-1">
+                <span class="w-3 h-3 rounded bg-green-200 dark:bg-green-700"></span>
+                Available
+            </span>
+            <span class="flex items-center gap-1">
+                <span class="w-3 h-3 rounded bg-yellow-200 dark:bg-yellow-700"></span>
+                Partial
+            </span>
+            <span class="flex items-center gap-1">
+                <span class="w-3 h-3 rounded bg-red-200 dark:bg-red-700"></span>
+                Unavailable
+            </span>
+        </div>
+    </div>
+
+    <button onclick="openReservationModal()"
+            class="px-4 py-2 bg-blue-600 text-white rounded-lg hover:bg-blue-700 flex items-center gap-2">
+        <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M12 4v16m8-8H4"/>
+        </svg>
+        New Reservation
+    </button>
+</div>
+
+<!-- Calendar Grid -->
+<div class="calendar-grid mb-8">
+    {% for month_data in calendar_data.months %}
+    <div class="month-card">
+        <h3 class="font-semibold text-gray-900 dark:text-white mb-2 text-center">
+            {{ month_data.short_name }} '{{ month_data.year_short }}
+        </h3>
+        <div class="day-grid">
+            <!-- Day headers -->
+            <div class="day-header">S</div>
+            <div class="day-header">M</div>
+            <div class="day-header">T</div>
+            <div class="day-header">W</div>
+            <div class="day-header">T</div>
+            <div class="day-header">F</div>
+            <div class="day-header">S</div>
+
+            <!-- Empty cells for alignment (first_weekday is 0=Mon, we need 0=Sun) -->
+            {% set first_day_offset = (month_data.first_weekday + 1) % 7 %}
+            {% for i in range(first_day_offset) %}
+            <div class="day-cell empty"></div>
+            {% endfor %}
+
+            <!-- Day cells -->
+            {% for day_num in range(1, month_data.num_days + 1) %}
+            {% set day_data = month_data.days[day_num] %}
+            {% set date_str = '%04d-%02d-%02d'|format(month_data.year, month_data.month, day_num) %}
+            {% set is_today = date_str == today %}
+            {% set has_cal_expiring = day_data.cal_expiring_on_day is defined and day_data.cal_expiring_on_day > 0 %}
+            <div class="day-cell neutral {% if is_today %}today ring-2 ring-seismo-orange{% endif %}"
+                 data-date="{{ date_str }}"
+                 data-available="{{ day_data.available }}"
+                 onclick="openDayPanel('{{ date_str }}')"
+                 title="Available: {{ day_data.available }}, Reserved: {{ day_data.reserved }}{% if has_cal_expiring %}, Cal expires: {{ day_data.cal_expiring_on_day }}{% endif %}">
+                {{ day_num }}
+                {% if has_cal_expiring %}
+                <span class="status-dot expired"></span>
+                {% endif %}
+            </div>
+            {% endfor %}
+        </div>
+    </div>
+    {% endfor %}
+</div>
+
+<!-- Month Navigation (centered below calendar) -->
+<div class="flex items-center justify-center gap-3 mb-8">
+    <a href="/fleet-calendar?year={{ prev_year }}&month={{ prev_month }}&device_type={{ device_type }}"
+       class="px-3 py-2 rounded-lg bg-gray-100 dark:bg-gray-700 hover:bg-gray-200 dark:hover:bg-gray-600 text-gray-700 dark:text-gray-300"
+       title="Previous month">
+        <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M15 19l-7-7 7-7"/>
+        </svg>
+    </a>
+    <span class="text-lg font-bold text-gray-900 dark:text-white px-3">
+        {{ calendar_data.months[0].name }} {{ calendar_data.months[0].year }} - {{ calendar_data.months[11].name }} {{ calendar_data.months[11].year }}
+    </span>
+    <a href="/fleet-calendar?year={{ next_year }}&month={{ next_month }}&device_type={{ device_type }}"
+       class="px-3 py-2 rounded-lg bg-gray-100 dark:bg-gray-700 hover:bg-gray-200 dark:hover:bg-gray-600 text-gray-700 dark:text-gray-300"
+       title="Next month">
+        <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 5l7 7-7 7"/>
+        </svg>
+    </a>
+    <a href="/fleet-calendar?device_type={{ device_type }}"
+       class="ml-2 px-4 py-2 rounded-lg bg-seismo-orange text-white hover:bg-orange-600">
+        Today
+    </a>
+</div>
+
+<!-- Active Reservations -->
+<div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-6 mb-8">
+    <h2 class="text-xl font-semibold text-gray-900 dark:text-white mb-4">Active Reservations</h2>
+    <div id="reservations-list"
+         hx-get="/api/fleet-calendar/reservations-list?year={{ start_year }}&month={{ start_month }}&device_type={{ device_type }}"
+         hx-trigger="load"
+         hx-swap="innerHTML">
+        <p class="text-gray-500">Loading reservations...</p>
+    </div>
+</div>
+
+<!-- Day Detail Slide Panel -->
+<div id="panel-backdrop" class="panel-backdrop" onclick="closeDayPanel()"></div>
+<div id="day-panel" class="slide-panel">
+    <div class="p-6" id="day-panel-content">
+        <!-- Content loaded via HTMX -->
+    </div>
+</div>
+
+<!-- Reservation Modal -->
+<div id="reservation-modal" class="fixed inset-0 z-50 hidden">
+    <div class="fixed inset-0 bg-black/50" onclick="closeReservationModal()"></div>
+    <div class="fixed inset-0 flex items-center justify-center p-4">
+        <div class="bg-white dark:bg-slate-800 rounded-xl shadow-2xl max-w-lg w-full max-h-[90vh] overflow-y-auto" onclick="event.stopPropagation()">
+            <div class="p-6">
+                <div class="flex items-center justify-between mb-6">
+                    <h2 class="text-xl font-semibold text-gray-900 dark:text-white">New Reservation</h2>
+                    <button onclick="closeReservationModal()" class="text-gray-400 hover:text-gray-600 dark:hover:text-gray-300">
+                        <svg class="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M6 18L18 6M6 6l12 12"/>
+                        </svg>
+                    </button>
+                </div>
+
+                <form id="reservation-form" onsubmit="submitReservation(event)">
+                    <!-- Name -->
+                    <div class="mb-4">
+                        <label class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-1">Reservation Name *</label>
+                        <input type="text" name="name" required
+                               placeholder="e.g., Job A - March Deployment"
+                               class="w-full px-3 py-2 border border-gray-300 dark:border-gray-600 rounded-lg bg-white dark:bg-slate-700 text-gray-900 dark:text-white focus:ring-2 focus:ring-blue-500">
+                    </div>
+
+                    <!-- Project (optional) -->
+                    <div class="mb-4">
+                        <label class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-1">Link to Project (optional)</label>
+                        <select name="project_id"
+                                class="w-full px-3 py-2 border border-gray-300 dark:border-gray-600 rounded-lg bg-white dark:bg-slate-700 text-gray-900 dark:text-white focus:ring-2 focus:ring-blue-500">
+                            <option value="">-- No project --</option>
+                            {% for project in projects %}
+                            <option value="{{ project.id }}">{{ project.name }}</option>
+                            {% endfor %}
+                        </select>
+                    </div>
+
+                    <!-- Date Range -->
+                    <div class="mb-4">
+                        <label class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-1">Start Date *</label>
+                        <input type="date" name="start_date" required
+                               class="w-full px-3 py-2 border border-gray-300 dark:border-gray-600 rounded-lg bg-white dark:bg-slate-700 text-gray-900 dark:text-white focus:ring-2 focus:ring-blue-500">
+                    </div>
+
+                    <div class="mb-4">
+                        <div class="flex items-center justify-between mb-1">
+                            <label class="block text-sm font-medium text-gray-700 dark:text-gray-300">End Date</label>
+                            <label class="flex items-center gap-2 cursor-pointer text-sm">
+                                <input type="checkbox" name="end_date_tbd" id="end_date_tbd"
+                                       onchange="toggleEndDateTBD()"
+                                       class="w-4 h-4 text-blue-600 focus:ring-blue-500 rounded border-gray-300 dark:border-gray-600">
+                                <span class="text-gray-600 dark:text-gray-400">TBD / Ongoing</span>
+                            </label>
+                        </div>
+                        <input type="date" name="end_date" id="end_date_input"
+                               class="w-full px-3 py-2 border border-gray-300 dark:border-gray-600 rounded-lg bg-white dark:bg-slate-700 text-gray-900 dark:text-white focus:ring-2 focus:ring-blue-500">
+                    </div>
+
+                    <!-- Estimated End Date (shown when TBD is checked) -->
+                    <div id="estimated-end-section" class="mb-4 hidden">
+                        <label class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-1">
+                            Estimated End Date <span class="text-gray-400 font-normal">(for planning)</span>
+                        </label>
+                        <input type="date" name="estimated_end_date"
+                               class="w-full px-3 py-2 border border-gray-300 dark:border-gray-600 rounded-lg bg-white dark:bg-slate-700 text-gray-900 dark:text-white focus:ring-2 focus:ring-blue-500">
+                        <p class="text-xs text-gray-500 mt-1">Used for calendar visualization only. Can be updated later.</p>
+                    </div>
+
+                    <!-- Assignment Type -->
+                    <div class="mb-4">
+                        <label class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">Assignment Type *</label>
+                        <div class="flex gap-4">
+                            <label class="flex items-center gap-2 cursor-pointer">
+                                <input type="radio" name="assignment_type" value="quantity" checked
+                                       onchange="toggleAssignmentType(this.value)"
+                                       class="text-blue-600 focus:ring-blue-500">
+                                <span class="text-gray-700 dark:text-gray-300">Reserve quantity</span>
+                            </label>
+                            <label class="flex items-center gap-2 cursor-pointer">
+                                <input type="radio" name="assignment_type" value="specific"
+                                       onchange="toggleAssignmentType(this.value)"
+                                       class="text-blue-600 focus:ring-blue-500">
+                                <span class="text-gray-700 dark:text-gray-300">Pick specific units</span>
+                            </label>
+                        </div>
+                    </div>
+
+                    <!-- Quantity (shown for quantity type) -->
+                    <div id="quantity-section" class="mb-4">
+                        <label class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-1">Units Needed</label>
+                        <input type="number" name="quantity_needed" min="1" value="1"
+                               onchange="updateCalendarAvailability()"
+                               oninput="updateCalendarAvailability()"
+                               class="w-32 px-3 py-2 border border-gray-300 dark:border-gray-600 rounded-lg bg-white dark:bg-slate-700 text-gray-900 dark:text-white focus:ring-2 focus:ring-blue-500">
+                        <p class="text-xs text-gray-500 mt-1">Calendar will highlight availability based on quantity</p>
+                    </div>
+
+                    <!-- Specific Units (shown for specific type) -->
+                    <div id="specific-section" class="mb-4 hidden">
+                        <label class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-1">Select Units</label>
+                        <div id="available-units-list" class="max-h-48 overflow-y-auto border border-gray-300 dark:border-gray-600 rounded-lg p-2">
+                            <p class="text-gray-500 text-sm">Select dates first to see available units</p>
+                        </div>
+                    </div>
+
+                    <!-- Color -->
+                    <div class="mb-4">
+                        <label class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-1">Color</label>
+                        <div class="flex gap-2">
+                            {% for color in ['#3B82F6', '#10B981', '#F59E0B', '#EF4444', '#8B5CF6', '#EC4899'] %}
+                            <label class="cursor-pointer">
+                                <input type="radio" name="color" value="{{ color }}" {% if loop.first %}checked{% endif %} class="sr-only peer">
+                                <span class="block w-8 h-8 rounded-full peer-checked:ring-2 peer-checked:ring-offset-2 peer-checked:ring-gray-900 dark:peer-checked:ring-white"
+                                      style="background-color: {{ color }}"></span>
+                            </label>
+                            {% endfor %}
+                        </div>
+                    </div>
+
+                    <!-- Notes -->
+                    <div class="mb-6">
+                        <label class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-1">Notes</label>
+                        <textarea name="notes" rows="2"
+                                  placeholder="Optional notes about this reservation"
+                                  class="w-full px-3 py-2 border border-gray-300 dark:border-gray-600 rounded-lg bg-white dark:bg-slate-700 text-gray-900 dark:text-white focus:ring-2 focus:ring-blue-500"></textarea>
+                    </div>
+
+                    <!-- Actions -->
+                    <div class="flex justify-end gap-3">
+                        <button type="button" onclick="closeReservationModal()"
+                                class="px-4 py-2 text-gray-700 dark:text-gray-300 hover:bg-gray-100 dark:hover:bg-gray-700 rounded-lg">
+                            Cancel
+                        </button>
+                        <button type="submit"
+                                class="px-4 py-2 bg-blue-600 text-white rounded-lg hover:bg-blue-700">
+                            Create Reservation
+                        </button>
+                    </div>
+                </form>
+            </div>
+        </div>
+    </div>
+</div>
+
+<script>
+const deviceType = '{{ device_type }}';
+const startYear = {{ start_year }};
+const startMonth = {{ start_month }};
+
+// Load today's stats
+document.addEventListener('DOMContentLoaded', function() {
+    loadTodayStats();
+});
+
+async function loadTodayStats() {
+    try {
+        const today = new Date().toISOString().split('T')[0];
+        const response = await fetch(`/api/fleet-calendar/day/${today}?device_type=${deviceType}`);
+        // Just update the stats from the day data response headers or a separate call
+        // For now, calculate from calendar data
+        const todayData = findTodayInCalendar();
+        if (todayData) {
+            document.getElementById('available-today').textContent = todayData.available;
+            document.getElementById('reserved-today').textContent = todayData.reserved;
+            document.getElementById('expiring-today').textContent = todayData.expiring_soon;
+            document.getElementById('expired-today').textContent = todayData.expired;
+        }
+    } catch (error) {
+        console.error('Error loading today stats:', error);
+    }
+}
+
+function findTodayInCalendar() {
+    const today = new Date();
+    const year = today.getFullYear();
+    const month = today.getMonth() + 1;
+    const day = today.getDate();
+    const calendarData = {{ calendar_data | tojson }};
+    // months is now an array, find the matching month
+    const monthData = calendarData.months.find(m => m.year === year && m.month === month);
+    if (monthData && monthData.days[day]) {
+        return monthData.days[day];
+    }
+    return null;
+}
+
+function openDayPanel(dateStr) {
+    const panel = document.getElementById('day-panel');
+    const backdrop = document.getElementById('panel-backdrop');
+    const content = document.getElementById('day-panel-content');
+
+    // Load content via HTMX
+    htmx.ajax('GET', `/api/fleet-calendar/day/${dateStr}?device_type=${deviceType}`, {
+        target: '#day-panel-content',
+        swap: 'innerHTML'
+    });
+
+    panel.classList.add('open');
+    backdrop.classList.add('open');
+}
+
+function closeDayPanel() {
+    const panel = document.getElementById('day-panel');
+    const backdrop = document.getElementById('panel-backdrop');
+    panel.classList.remove('open');
+    backdrop.classList.remove('open');
+}
+
+let reservationModeActive = false;
+
+function openReservationModal() {
+    document.getElementById('reservation-modal').classList.remove('hidden');
+    reservationModeActive = true;
+    // Show reservation legend, hide main legend
+    document.getElementById('main-legend').classList.add('md:hidden');
+    document.getElementById('main-legend').classList.remove('md:flex');
+    document.getElementById('reservation-legend').classList.remove('md:hidden');
+    document.getElementById('reservation-legend').classList.add('md:flex');
+    // Trigger availability update
+    updateCalendarAvailability();
+}
+
+function closeReservationModal() {
+    document.getElementById('reservation-modal').classList.add('hidden');
+    document.getElementById('reservation-form').reset();
+    reservationModeActive = false;
+    // Restore main legend
+    document.getElementById('main-legend').classList.remove('md:hidden');
+    document.getElementById('main-legend').classList.add('md:flex');
+    document.getElementById('reservation-legend').classList.add('md:hidden');
+    document.getElementById('reservation-legend').classList.remove('md:flex');
+    // Reset calendar colors
+    resetCalendarColors();
+}
+
+function resetCalendarColors() {
+    document.querySelectorAll('.day-cell:not(.empty)').forEach(cell => {
+        cell.classList.remove('reservation-available', 'reservation-partial', 'reservation-unavailable');
+        cell.classList.add('neutral');
+    });
+}
+
+function updateCalendarAvailability() {
+    if (!reservationModeActive) return;
+
+    const quantityInput = document.querySelector('input[name="quantity_needed"]');
+    const quantity = parseInt(quantityInput?.value) || 1;
+
+    // Update each day cell based on available units vs quantity needed
+    document.querySelectorAll('.day-cell:not(.empty)').forEach(cell => {
+        const available = parseInt(cell.dataset.available) || 0;
+
+        // Remove all status classes
+        cell.classList.remove('neutral', 'reservation-available', 'reservation-partial', 'reservation-unavailable');
+
+        if (available >= quantity) {
+            cell.classList.add('reservation-available');
+        } else if (available > 0) {
+            cell.classList.add('reservation-partial');
+        } else {
+            cell.classList.add('reservation-unavailable');
+        }
+    });
+}
+
+function toggleEndDateTBD() {
+    const checkbox = document.getElementById('end_date_tbd');
+    const endDateInput = document.getElementById('end_date_input');
+    const estimatedSection = document.getElementById('estimated-end-section');
+
+    if (checkbox.checked) {
+        endDateInput.disabled = true;
+        endDateInput.value = '';
+        endDateInput.classList.add('opacity-50', 'cursor-not-allowed');
+        estimatedSection.classList.remove('hidden');
+    } else {
+        endDateInput.disabled = false;
+        endDateInput.classList.remove('opacity-50', 'cursor-not-allowed');
+        estimatedSection.classList.add('hidden');
+    }
+}
+
+function toggleAssignmentType(type) {
+    const quantitySection = document.getElementById('quantity-section');
+    const specificSection = document.getElementById('specific-section');
+
+    if (type === 'quantity') {
+        quantitySection.classList.remove('hidden');
+        specificSection.classList.add('hidden');
+    } else {
+        quantitySection.classList.add('hidden');
+        specificSection.classList.remove('hidden');
+        // Load available units based on selected dates
+        loadAvailableUnits();
+    }
+}
+
+async function loadAvailableUnits() {
+    const startDate = document.querySelector('input[name="start_date"]').value;
+    const endDate = document.querySelector('input[name="end_date"]').value;
+
+    if (!startDate || !endDate) {
+        document.getElementById('available-units-list').innerHTML =
+            '<p class="text-gray-500 text-sm">Select dates first to see available units</p>';
+        return;
+    }
+
+    try {
+        const response = await fetch(
+            `/api/fleet-calendar/availability?start_date=${startDate}&end_date=${endDate}&device_type=${deviceType}`
+        );
+        const data = await response.json();
+
+        if (data.available_units.length === 0) {
+            document.getElementById('available-units-list').innerHTML =
+                '<p class="text-gray-500 text-sm">No units available for this period</p>';
+            return;
+        }
+
+        let html = '';
+        for (const unit of data.available_units) {
+            html += `
+                <label class="flex items-center gap-2 p-2 hover:bg-gray-50 dark:hover:bg-gray-700 rounded cursor-pointer">
+                    <input type="checkbox" name="unit_ids" value="${unit.id}"
+                           class="text-blue-600 focus:ring-blue-500 rounded">
+                    <span class="text-gray-900 dark:text-white font-medium">${unit.id}</span>
+                    <span class="text-gray-500 text-sm">Cal: ${unit.last_calibrated || 'N/A'}</span>
+                    ${unit.calibration_status === 'expiring_soon' ?
+                        '<span class="text-yellow-600 text-xs">Expiring soon</span>' : ''}
+                </label>
+            `;
+        }
+        document.getElementById('available-units-list').innerHTML = html;
+    } catch (error) {
+        console.error('Error loading available units:', error);
+    }
+}
+
+// Watch for date changes to reload available units
+document.addEventListener('DOMContentLoaded', function() {
+    const startInput = document.querySelector('input[name="start_date"]');
+    const endInput = document.querySelector('input[name="end_date"]');
+
+    if (startInput && endInput) {
+        startInput.addEventListener('change', function() {
+            if (document.querySelector('input[name="assignment_type"]:checked').value === 'specific') {
+                loadAvailableUnits();
+            }
+        });
+        endInput.addEventListener('change', function() {
+            if (document.querySelector('input[name="assignment_type"]:checked').value === 'specific') {
+                loadAvailableUnits();
+            }
+        });
+    }
+});
+
+async function submitReservation(event) {
+    event.preventDefault();
+
+    const form = event.target;
+    const formData = new FormData(form);
+    const endDateTbd = formData.get('end_date_tbd') === 'on';
+
+    const data = {
+        name: formData.get('name'),
+        project_id: formData.get('project_id') || null,
+        start_date: formData.get('start_date'),
+        end_date: endDateTbd ? null : formData.get('end_date'),
+        end_date_tbd: endDateTbd,
+        estimated_end_date: endDateTbd ? (formData.get('estimated_end_date') || null) : null,
+        assignment_type: formData.get('assignment_type'),
+        device_type: deviceType,
+        color: formData.get('color'),
+        notes: formData.get('notes') || null
+    };
+
+    // Validate: need either end_date or TBD checked
+    if (!data.end_date && !data.end_date_tbd) {
+        alert('Please enter an end date or check "TBD / Ongoing"');
+        return;
+    }
+
+    if (data.assignment_type === 'quantity') {
+        data.quantity_needed = parseInt(formData.get('quantity_needed'));
+    } else {
+        data.unit_ids = formData.getAll('unit_ids');
+    }
+
+    try {
+        const response = await fetch('/api/fleet-calendar/reservations', {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify(data)
+        });
+
+        const result = await response.json();
+
+        if (result.success) {
+            closeReservationModal();
+            // Reload the page to refresh calendar
+            window.location.reload();
+        } else {
+            alert('Error creating reservation: ' + (result.detail || 'Unknown error'));
+        }
+    } catch (error) {
+        console.error('Error:', error);
+        alert('Error creating reservation');
+    }
+}
+
+// Close panels on escape key
+document.addEventListener('keydown', function(e) {
+    if (e.key === 'Escape') {
+        closeDayPanel();
+        closeReservationModal();
+    }
+});
+</script>
+{% endblock %}
diff --git a/templates/partials/fleet_calendar/available_units.html b/templates/partials/fleet_calendar/available_units.html
new file mode 100644
index 0000000..9190166
--- /dev/null
+++ b/templates/partials/fleet_calendar/available_units.html
@@ -0,0 +1,40 @@
+<!-- Available Units for Assignment -->
+{% if units %}
+<div class="space-y-1">
+    {% for unit in units %}
+    <label class="flex items-center gap-3 p-2 hover:bg-gray-50 dark:hover:bg-gray-700 rounded cursor-pointer">
+        <input type="checkbox" name="unit_ids" value="{{ unit.id }}"
+               class="w-4 h-4 text-blue-600 focus:ring-blue-500 rounded border-gray-300 dark:border-gray-600">
+        <span class="font-medium text-gray-900 dark:text-white">{{ unit.id }}</span>
+        <span class="text-sm text-gray-500 dark:text-gray-400 flex-1">
+            {% if unit.last_calibrated %}
+            Cal: {{ unit.last_calibrated }}
+            {% else %}
+            No cal date
+            {% endif %}
+        </span>
+        {% if unit.calibration_status == 'expiring_soon' %}
+        <span class="text-xs px-2 py-0.5 bg-yellow-100 dark:bg-yellow-900/30 text-yellow-700 dark:text-yellow-400 rounded-full">
+            Expiring soon
+        </span>
+        {% endif %}
+        {% if unit.deployed %}
+        <span class="text-xs px-2 py-0.5 bg-green-100 dark:bg-green-900/30 text-green-700 dark:text-green-400 rounded-full">
+            Deployed
+        </span>
+        {% else %}
+        <span class="text-xs px-2 py-0.5 bg-gray-100 dark:bg-gray-700 text-gray-600 dark:text-gray-400 rounded-full">
+            Benched
+        </span>
+        {% endif %}
+    </label>
+    {% endfor %}
+</div>
+{% else %}
+<p class="text-gray-500 dark:text-gray-400 text-sm py-4 text-center">
+    No units available for this date range.
+    {% if start_date and end_date %}
+    <br><span class="text-xs">All units are either reserved, have expired calibrations, or are retired.</span>
+    {% endif %}
+</p>
+{% endif %}
diff --git a/templates/partials/fleet_calendar/day_detail.html b/templates/partials/fleet_calendar/day_detail.html
new file mode 100644
index 0000000..792406a
--- /dev/null
+++ b/templates/partials/fleet_calendar/day_detail.html
@@ -0,0 +1,186 @@
+<!-- Day Detail Panel Content -->
+<div class="flex items-center justify-between mb-6">
+    <h2 class="text-xl font-semibold text-gray-900 dark:text-white">{{ date_display }}</h2>
+    <button onclick="closeDayPanel()" class="text-gray-400 hover:text-gray-600 dark:hover:text-gray-300">
+        <svg class="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M6 18L18 6M6 6l12 12"/>
+        </svg>
+    </button>
+</div>
+
+<!-- Summary Stats -->
+<div class="grid grid-cols-2 gap-3 mb-6">
+    <div class="bg-green-50 dark:bg-green-900/20 rounded-lg p-3 text-center">
+        <p class="text-2xl font-bold text-green-700 dark:text-green-300">{{ day_data.counts.available }}</p>
+        <p class="text-xs text-green-600 dark:text-green-400">Available</p>
+    </div>
+    <div class="bg-blue-50 dark:bg-blue-900/20 rounded-lg p-3 text-center">
+        <p class="text-2xl font-bold text-blue-700 dark:text-blue-300">{{ day_data.counts.reserved }}</p>
+        <p class="text-xs text-blue-600 dark:text-blue-400">Reserved</p>
+    </div>
+    <div class="bg-yellow-50 dark:bg-yellow-900/20 rounded-lg p-3 text-center">
+        <p class="text-2xl font-bold text-yellow-700 dark:text-yellow-300">{{ day_data.counts.expiring_soon }}</p>
+        <p class="text-xs text-yellow-600 dark:text-yellow-400">Expiring Soon</p>
+    </div>
+    <div class="bg-red-50 dark:bg-red-900/20 rounded-lg p-3 text-center">
+        <p class="text-2xl font-bold text-red-700 dark:text-red-300">{{ day_data.counts.expired }}</p>
+        <p class="text-xs text-red-600 dark:text-red-400">Cal. Expired</p>
+    </div>
+</div>
+
+<!-- Calibration Expiring TODAY - Important alert -->
+{% if day_data.cal_expiring_today %}
+<div class="mb-6 p-3 bg-red-50 dark:bg-red-900/30 border border-red-200 dark:border-red-800 rounded-lg">
+    <h3 class="text-sm font-semibold text-red-700 dark:text-red-400 mb-2 flex items-center gap-2">
+        <svg class="w-4 h-4" fill="currentColor" viewBox="0 0 20 20">
+            <path fill-rule="evenodd" d="M8.257 3.099c.765-1.36 2.722-1.36 3.486 0l5.58 9.92c.75 1.334-.213 2.98-1.742 2.98H4.42c-1.53 0-2.493-1.646-1.743-2.98l5.58-9.92zM11 13a1 1 0 11-2 0 1 1 0 012 0zm-1-8a1 1 0 00-1 1v3a1 1 0 002 0V6a1 1 0 00-1-1z" clip-rule="evenodd"/>
+        </svg>
+        Calibration Expires Today ({{ day_data.cal_expiring_today|length }})
+    </h3>
+    <div class="space-y-1">
+        {% for unit in day_data.cal_expiring_today %}
+        <div class="flex items-center justify-between p-2 bg-white dark:bg-gray-800 rounded text-sm">
+            <a href="/unit/{{ unit.id }}" class="font-medium text-red-600 dark:text-red-400 hover:underline">
+                {{ unit.id }}
+            </a>
+            <span class="text-red-500 text-xs">
+                Last cal: {{ unit.last_calibrated }}
+            </span>
+        </div>
+        {% endfor %}
+    </div>
+</div>
+{% endif %}
+
+<!-- Reservations on this date -->
+{% if day_data.reservations %}
+<div class="mb-6">
+    <h3 class="text-sm font-semibold text-gray-700 dark:text-gray-300 mb-3">Reservations</h3>
+    {% for res in day_data.reservations %}
+    <div class="reservation-bar mb-2" style="background-color: {{ res.color }}20; border-left: 4px solid {{ res.color }};">
+        <div class="flex-1">
+            <p class="font-medium text-gray-900 dark:text-white">{{ res.name }}</p>
+            <p class="text-xs text-gray-500 dark:text-gray-400">
+                {{ res.start_date }} - {{ res.end_date }}
+            </p>
+        </div>
+        <div class="text-right">
+            <p class="font-semibold text-gray-900 dark:text-white">
+                {% if res.assignment_type == 'quantity' %}
+                {{ res.assigned_count }}/{{ res.quantity_needed or '?' }}
+                {% else %}
+                {{ res.assigned_count }} units
+                {% endif %}
+            </p>
+        </div>
+    </div>
+    {% endfor %}
+</div>
+{% endif %}
+
+<!-- Available Units -->
+{% if day_data.available_units %}
+<div class="mb-6">
+    <h3 class="text-sm font-semibold text-gray-700 dark:text-gray-300 mb-3">
+        Available Units ({{ day_data.available_units|length }})
+    </h3>
+    <div class="max-h-48 overflow-y-auto space-y-1">
+        {% for unit in day_data.available_units %}
+        <div class="flex items-center justify-between p-2 bg-gray-50 dark:bg-gray-700/50 rounded text-sm">
+            <a href="/unit/{{ unit.id }}" class="font-medium text-blue-600 dark:text-blue-400 hover:underline">
+                {{ unit.id }}
+            </a>
+            <span class="text-gray-500 dark:text-gray-400 text-xs">
+                {% if unit.last_calibrated %}
+                Cal: {{ unit.last_calibrated }}
+                {% else %}
+                No cal date
+                {% endif %}
+            </span>
+        </div>
+        {% endfor %}
+    </div>
+</div>
+{% endif %}
+
+<!-- Reserved Units -->
+{% if day_data.reserved_units %}
+<div class="mb-6">
+    <h3 class="text-sm font-semibold text-gray-700 dark:text-gray-300 mb-3">
+        Reserved Units ({{ day_data.reserved_units|length }})
+    </h3>
+    <div class="max-h-48 overflow-y-auto space-y-1">
+        {% for unit in day_data.reserved_units %}
+        <div class="flex items-center justify-between p-2 bg-blue-50 dark:bg-blue-900/20 rounded text-sm">
+            <a href="/unit/{{ unit.id }}" class="font-medium text-blue-600 dark:text-blue-400 hover:underline">
+                {{ unit.id }}
+            </a>
+            <span class="text-blue-600 dark:text-blue-400 text-xs">
+                {{ unit.reservation_name }}
+            </span>
+        </div>
+        {% endfor %}
+    </div>
+</div>
+{% endif %}
+
+<!-- Calibration Expired -->
+{% if day_data.expired_units %}
+<div class="mb-6">
+    <h3 class="text-sm font-semibold text-red-600 dark:text-red-400 mb-3">
+        Calibration Expired ({{ day_data.expired_units|length }})
+    </h3>
+    <div class="max-h-48 overflow-y-auto space-y-1">
+        {% for unit in day_data.expired_units %}
+        <div class="flex items-center justify-between p-2 bg-red-50 dark:bg-red-900/20 rounded text-sm">
+            <a href="/unit/{{ unit.id }}" class="font-medium text-red-600 dark:text-red-400 hover:underline">
+                {{ unit.id }}
+            </a>
+            <span class="text-red-500 text-xs">
+                Expired: {{ unit.expiry_date }}
+            </span>
+        </div>
+        {% endfor %}
+    </div>
+</div>
+{% endif %}
+
+<!-- Needs Calibration -->
+{% if day_data.needs_calibration_units %}
+<div class="mb-6">
+    <h3 class="text-sm font-semibold text-gray-600 dark:text-gray-400 mb-3">
+        Needs Calibration Date ({{ day_data.needs_calibration_units|length }})
+    </h3>
+    <div class="max-h-32 overflow-y-auto space-y-1">
+        {% for unit in day_data.needs_calibration_units %}
+        <div class="flex items-center justify-between p-2 bg-gray-100 dark:bg-gray-700/50 rounded text-sm">
+            <a href="/unit/{{ unit.id }}" class="font-medium text-gray-600 dark:text-gray-400 hover:underline">
+                {{ unit.id }}
+            </a>
+            <span class="text-gray-400 text-xs">No cal date set</span>
+        </div>
+        {% endfor %}
+    </div>
+</div>
+{% endif %}
+
+<!-- Expiring Soon (informational) -->
+{% if day_data.expiring_soon_units %}
+<div class="mb-6">
+    <h3 class="text-sm font-semibold text-yellow-600 dark:text-yellow-400 mb-3">
+        Calibration Expiring Soon ({{ day_data.expiring_soon_units|length }})
+    </h3>
+    <div class="max-h-32 overflow-y-auto space-y-1">
+        {% for unit in day_data.expiring_soon_units %}
+        <div class="flex items-center justify-between p-2 bg-yellow-50 dark:bg-yellow-900/20 rounded text-sm">
+            <a href="/unit/{{ unit.id }}" class="font-medium text-yellow-700 dark:text-yellow-400 hover:underline">
+                {{ unit.id }}
+            </a>
+            <span class="text-yellow-600 text-xs">
+                Expires: {{ unit.expiry_date }}
+            </span>
+        </div>
+        {% endfor %}
+    </div>
+</div>
+{% endif %}
diff --git a/templates/partials/fleet_calendar/reservations_list.html b/templates/partials/fleet_calendar/reservations_list.html
new file mode 100644
index 0000000..4de84eb
--- /dev/null
+++ b/templates/partials/fleet_calendar/reservations_list.html
@@ -0,0 +1,103 @@
+<!-- Reservations List -->
+{% if reservations %}
+<div class="space-y-3">
+    {% for item in reservations %}
+    {% set res = item.reservation %}
+    <div class="flex items-center justify-between p-4 rounded-lg border border-gray-200 dark:border-gray-700 hover:bg-gray-50 dark:hover:bg-gray-700/50 transition-colors"
+         style="border-left: 4px solid {{ res.color }};">
+        <div class="flex-1">
+            <div class="flex items-center gap-2">
+                <h3 class="font-semibold text-gray-900 dark:text-white">{{ res.name }}</h3>
+                {% if item.has_conflicts %}
+                <span class="px-2 py-0.5 text-xs font-medium bg-red-100 dark:bg-red-900/30 text-red-700 dark:text-red-400 rounded-full"
+                      title="{{ item.conflict_count }} unit(s) have calibration expiring during this job">
+                    {{ item.conflict_count }} conflict{{ 's' if item.conflict_count != 1 else '' }}
+                </span>
+                {% endif %}
+            </div>
+            <p class="text-sm text-gray-500 dark:text-gray-400 mt-1">
+                {{ res.start_date.strftime('%b %d, %Y') }} -
+                {% if res.end_date %}
+                    {{ res.end_date.strftime('%b %d, %Y') }}
+                {% elif res.end_date_tbd %}
+                    <span class="text-yellow-600 dark:text-yellow-400 font-medium">TBD</span>
+                    {% if res.estimated_end_date %}
+                    <span class="text-gray-400">(est. {{ res.estimated_end_date.strftime('%b %d, %Y') }})</span>
+                    {% endif %}
+                {% else %}
+                    <span class="text-yellow-600 dark:text-yellow-400">Ongoing</span>
+                {% endif %}
+            </p>
+            {% if res.notes %}
+            <p class="text-sm text-gray-400 dark:text-gray-500 mt-1">{{ res.notes }}</p>
+            {% endif %}
+        </div>
+        <div class="text-right ml-4">
+            <p class="text-lg font-bold text-gray-900 dark:text-white">
+                {% if res.assignment_type == 'quantity' %}
+                {{ item.assigned_count }}/{{ res.quantity_needed or '?' }}
+                {% else %}
+                {{ item.assigned_count }}
+                {% endif %}
+            </p>
+            <p class="text-xs text-gray-500 dark:text-gray-400">
+                {{ 'units needed' if res.assignment_type == 'quantity' else 'units assigned' }}
+            </p>
+        </div>
+        <div class="ml-4 flex items-center gap-2">
+            <button onclick="editReservation('{{ res.id }}')"
+                    class="p-2 text-gray-400 hover:text-blue-600 dark:hover:text-blue-400 rounded-lg hover:bg-gray-100 dark:hover:bg-gray-700"
+                    title="Edit reservation">
+                <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                    <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M11 5H6a2 2 0 00-2 2v11a2 2 0 002 2h11a2 2 0 002-2v-5m-1.414-9.414a2 2 0 112.828 2.828L11.828 15H9v-2.828l8.586-8.586z"/>
+                </svg>
+            </button>
+            <button onclick="deleteReservation('{{ res.id }}', '{{ res.name }}')"
+                    class="p-2 text-gray-400 hover:text-red-600 dark:hover:text-red-400 rounded-lg hover:bg-gray-100 dark:hover:bg-gray-700"
+                    title="Delete reservation">
+                <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                    <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M19 7l-.867 12.142A2 2 0 0116.138 21H7.862a2 2 0 01-1.995-1.858L5 7m5 4v6m4-6v6m1-10V4a1 1 0 00-1-1h-4a1 1 0 00-1 1v3M4 7h16"/>
+                </svg>
+            </button>
+        </div>
+    </div>
+    {% endfor %}
+</div>
+
+<script>
+async function deleteReservation(id, name) {
+    if (!confirm(`Delete reservation "${name}"?\n\nThis will remove all unit assignments.`)) {
+        return;
+    }
+
+    try {
+        const response = await fetch(`/api/fleet-calendar/reservations/${id}`, {
+            method: 'DELETE'
+        });
+
+        if (response.ok) {
+            window.location.reload();
+        } else {
+            const data = await response.json();
+            alert('Error: ' + (data.detail || 'Failed to delete'));
+        }
+    } catch (error) {
+        console.error('Error:', error);
+        alert('Error deleting reservation');
+    }
+}
+
+function editReservation(id) {
+    // For now, just show alert - can implement edit modal later
+    alert('Edit functionality coming soon. For now, delete and recreate the reservation.');
+}
+</script>
+{% else %}
+<div class="text-center py-8">
+    <svg class="w-12 h-12 mx-auto text-gray-400 dark:text-gray-500 mb-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M8 7V3m8 4V3m-9 8h10M5 21h14a2 2 0 002-2V7a2 2 0 00-2-2H5a2 2 0 00-2 2v12a2 2 0 002 2z"/>
+    </svg>
+    <p class="text-gray-500 dark:text-gray-400">No reservations for {{ year }}</p>
+    <p class="text-sm text-gray-400 dark:text-gray-500 mt-1">Click "New Reservation" to plan unit assignments</p>
+</div>
+{% endif %}