DOT Hours of Service Calculator
Track your remaining driving and on-duty hours under FMCSA Hours of Service rules. Covers the 11-hour driving limit, 14-hour window, and 70-hour/8-day cycle.
Results
Visualization
How It Works
The FMCSA Hours of Service (HOS) regulations limit how long commercial motor vehicle drivers can operate before taking mandatory rest. The three main limits are the 11-hour driving window, the 14-hour on-duty window, and the 70-hour/8-day cycle. This calculator helps you stay compliant and avoid costly violations.
The Formula
Remaining On-Duty = 14 - On-Duty Hours Today
Remaining Cycle = 70 - Hours Used in 8-Day Cycle
Effective Hours = min(Remaining Driving, Remaining On-Duty, Remaining Cycle)
Variables
- 11 — Maximum driving hours allowed after 10 consecutive hours off duty
- 14 — Maximum on-duty window (driving + all other work) after coming on duty
- 70 — Maximum on-duty hours in any 8-consecutive-day period
- 34 — Consecutive off-duty hours needed for a full cycle restart
Worked Example
A driver has driven 8 hours today, been on duty 10 hours total, and used 50 of 70 cycle hours. Remaining driving: 11 - 8 = 3 hours. Remaining on-duty: 14 - 10 = 4 hours. Remaining cycle: 70 - 50 = 20 hours. Effective available: 3 hours (the smallest limit).
Practical Tips
- The 14-hour on-duty clock starts when you first go on duty and cannot be paused, even with off-duty breaks.
- You must take a 30-minute break after 8 cumulative hours of driving before driving again.
- A 34-hour restart resets your 70-hour clock to zero but must include two periods between 1 AM and 5 AM.
- Sleeper berth splits (7/3 or 8/2) can effectively extend your driving day under current rules.
- ELD violations carry fines up to $16,000 per offense. Keeping accurate logs is essential.
Frequently Asked Questions
What is the 11-hour driving rule?
After 10 consecutive hours off duty, you may drive up to 11 hours before needing another 10-hour off-duty period.
What is the 14-hour on-duty limit?
You cannot drive after the 14th consecutive hour after coming on duty. This window runs continuously and cannot be paused.
How does the 70-hour/8-day rule work?
You cannot drive after being on duty 70 hours in any 8 consecutive days. Hours from day 9 and beyond drop off the cycle.
What qualifies as a 34-hour restart?
A restart requires 34 consecutive hours off duty, which resets your 70-hour cycle clock to zero.
Are there exceptions to HOS rules?
Yes, short-haul exemption (150 air-mile radius), adverse driving conditions, and emergency declarations can modify the rules.