Fleet Service Due Miles & Calendar Planner

Method and units

Due odometer = last-service odometer + distance interval. Due date = service date plus whole calendar months, clamped to the last valid day of the destination month. Report each remaining margin and which due point occurs first; a past due date or odometer is shown as overdue.

Worked example

A service recorded at 20,000 mi on 2026-01-31 with a 5,000 mi / 6 month interval is due at 25,000 mi or 2026-07-31. At 24,200 mi on 2026-06-15, 800 mi and 46 days remain.

Supported inputs and interpretation

Odometers 0–2,000,000 mi; interval 1–100,000 mi; calendar interval 1–120 whole months; dates must be valid ISO calendar dates. Results are rounded for display only; internal calculations retain full JavaScript precision. Entered measurements and assumptions determine the answer.

References and limitations

The equations here use the stated unit conversions and geometric or accounting relationships; no empirical vehicle limits or manufacturer presets are supplied.

Intervals and current readings are supplied by you. This does not prescribe service, combine severe-duty schedules or replace the manufacturer's manual; compare the exact vehicle's time, distance and operating-condition requirements.

Related calculators

• Lease Mileage Pace Allowance

This planner performs the stated arithmetic; it is not a vehicle inspection, engineering approval, manufacturer's recommendation or professional review.