Hours of service

Four clocks run at once, and you are legal only while all four still have room in them. Here is what each one is, what stops it, and a calculator that tells you which one runs out first.

ClockLimitStartsResets
Driving11 hours After 10 consecutive hours off duty Another 10 consecutive hours off duty
Window14 consecutive hours The moment you come on duty Another 10 consecutive hours off duty
Break30 minutes After 8 cumulative hours of driving Any 30 consecutive minutes not driving
Cycle60 hours in 7 days, or 70 in 8 Rolling — it never stops Hours drop off day by day, or a 34-hour restart

Hours of service calculator

Everything stays in your browser. Nothing is sent anywhere, and no account is needed.

The part that catches people

The 11-hour driving clock and the 14-hour window are not the same thing and do not behave the same way. Driving time only accumulates while you drive. The window is consecutive — it runs through your 30-minute break, through a three-hour detention at a dock, through lunch and through traffic. Stopping does not buy you time; it spends it.

So a 06:00 start means you cannot drive after 20:00, whatever you did in between. If a receiver holds you four hours, those hours came out of your driving day, not out of nowhere — which is why detention costs more than it pays. The only pause available is a qualifying sleeper-berth split.

Each rule in full

How many hours can a truck driver drive?Eleven hours of driving inside a 14-hour window. What stops each clock, and what only looks like it does.Split sleeper berth calculatorCheck whether a split qualifies, and see which period pauses the window.The 30-minute break ruleTriggered by driving time, not duty time — and on-duty not driving counts.The 70-hour 8-day ruleThe rolling cycle, how hours come back, and when the 34-hour restart pays.Personal conveyance rulesNo mileage cap, one hard test: the movement must not advance the load.Adverse driving conditions exceptionTwo extra hours, for conditions you could not have known about at dispatch.The 150 air-mile short-haul exemption150 air miles, 14 hours, back to the same place — and what you lose at 151.

Planning a day around them

The rules set the outside edge; the trip decides whether you get near it. A 600-mile run at an achievable 55 mph average is around 11 hours of driving before you have fuelled, scaled or eaten — which is the whole 11-hour clock with nothing spare for a late dock.

The calculator plans the trip against these limits: it works out where the driving time runs out on the actual route, and shows the truck stops near that point rather than leaving you to find one at hour thirteen.

Questions

What are the hours of service rules?

Four limits run at the same time for a property-carrying driver: 11 hours of driving, a 14-hour window from when you come on duty, a 30-minute break after 8 cumulative hours of driving, and 60 hours in 7 days or 70 in 8. You are legal only while all four still have room.

Is there a free hours of service calculator?

The one on this page. Enter when you came on duty, what you have driven and where your cycle stands, and it shows which clock runs out first and at what time. Nothing is sent anywhere and no account is needed.

Does the 14-hour window stop if I take a break?

No. The 14-hour window is consecutive time and it keeps running through breaks, meals, loading and traffic. The only things that pause it are a qualifying sleeper-berth split and the end of the day. This catches more drivers out than any other part of the rule.

What happens if I go over?

An officer can place you out of service on the spot — usually for 10 consecutive hours, or until you are back in compliance. There are civil penalties, and the violation goes on your carrier's safety record with a severity weight attached.

Do these rules apply to me?

They apply to interstate property-carrying commercial motor vehicles. Passenger-carrying drivers have their own limits, intrastate-only operations follow state rules that are often similar but not identical, and there are industry exemptions. When in doubt, the text at 49 CFR 395 decides it.

What this is. A plain-English summary of the federal hours-of-service rules for property-carrying drivers, at 49 CFR 395. Passenger-carrying drivers work to a different set of limits, intrastate-only operations follow their state's rules, and exemptions exist for particular industries. Rules change — check the current text at ecfr.gov or with FMCSA before you rely on any of it. This is not legal advice, and your ELD and your carrier's policy both still apply.