34-Hour Restart Calculator
When the weekly clock comes back, and whether the restart beats the recap.
OpenHours of Service Calculator
Four clocks run at once under 49 CFR §395.3 and the day ends when the first of them runs out. This works all four from the same duty events, so you can see whether it is the driving hours, the window, the break or the week that will park you.
Today's clocks
Pre-filled with a realistic mid-shift day. Change any figure — the readouts update as you type.
- Driving time leftof 11 h
- 5h 30m
- Window leftof 14 h
- 6h 00m
- Driving before a break30 min needed
- 2h 30m
- 70-hour week leftover 8 days
- 18h 00m
What stops you first
2h 30m
30-minute break, compliant
What it checks
Each readout is one subtraction against the limit in §395.3, and the big figure at the bottom is simply the smallest of the four. That is the whole rule, and stating it that plainly is the point: drivers get violations because they watch one clock, not because the arithmetic is hard.
The dot beside each row turns amber inside the last hour and red at zero. Amber is where a decision still exists — take the break now, or start looking for parking.
Worked example
A driver came on duty at 06:00 after a full 10 off, spent two and a half hours at a shipper, and has 5.5 driving hours behind them at 14:00.
| Clock | Used | Limit | Left |
|---|---|---|---|
| Driving | 5.5 | 11 | 5.5 |
| Window | 8.0 | 14 | 6.0 |
| Break | 5.5 | 8 | 2.5 |
| Week | 52.0 | 70 | 18.0 |
The break is binding at two and a half hours, not the driving clock at five and a half. Take the 30 minutes at a scale or a receiver and the next binding figure becomes the window, at six hours — which is what actually decides how far this load gets today.
The rule it comes from
49 CFR §395.3 — 10 hours off before driving; 11 driving hours inside a 14-hour window; a 30-minute interruption before 8 hours of driving have passed; 60 hours in 7 days or 70 in 8 depending on whether the carrier operates every day; a period may end with 34 consecutive hours off duty.
This calculator covers the property-carrying limits. Passenger-carrying drivers work to §395.5, and the sleeper-berth split in §395.1(g) can move the window in ways a single subtraction does not capture — if you are running a split, check the ELD's own calculation against the regulation rather than this page.