Federal hours-of-service rules cap driving and on-duty time. Remaining drive time is the lesser of what’s left on the 11-hour drive limit and the 14-hour duty window — a safety and compliance must.
The example
6 driven, 9 on duty.
| A | B | |
|---|---|---|
| 1 | Item | Value |
| 2 | 11−6 vs 14−9 | 5 vs 5 |
| 3 | Remaining | → 5 hrs |
The formula
The formula:
How it works
How it works:
- The 11-hour rule: max 11 hours driving after 10 hours off.
- The 14-hour rule: no driving beyond the 14th hour after coming on duty.
- Remaining drive time = MIN of (11 − driven) and (14 − on-duty).
- Floor with MAX(…, 0) so it never shows negative once a limit is hit.
The tighter clock wins — and the 14-hour window does not pause. Unlike the 11-hour drive limit, the 14-hour duty window keeps running through breaks, fuel stops, and loading, so it often becomes the binding constraint late in a shift. Always take the MIN of both. This is a simplified illustration of the basic property-carrying limits; the 30-minute break, 70-hour/8-day, and sleeper rules also apply — follow current FMCSA regulations and your ELD.
Try it: interactive demo
Hours driven and hours on duty.
Variations
Floored at zero
No negatives:
Drive-limit only
11-hour rule:
Window-only
14-hour rule:
Pitfalls & errors
Tighter clock governs. Take the MIN of the two limits.
14-hour doesn’t pause. The duty window runs through breaks.
Simplified. Real HOS adds breaks, 70-hour, and sleeper rules — follow FMCSA.
Practice workbook
Frequently asked questions
How do I calculate HOS hours remaining in Excel?
Why is the 14-hour rule often binding?
Is this the full HOS rule?
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