Fatigue Break Calculator
A long shift or drive to site should be broken up with rest, not done in one go. This calculator works out how many breaks a stint needs based on your maximum continuous work time, then adds them up to show the total elapsed time door-to-door — useful for planning a drive-in day or a long operating shift.
Enter Values
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Enter the total hours you have to work or drive.
- Set the maximum continuous hours you will do before stopping (defaults to 5) and how long each break is in minutes (defaults to 30).
- Read the number of breaks required, the total time spent on breaks, and the total elapsed time including those breaks.
How it works
The stint is divided into segments no longer than your maximum continuous hours. Breaks = ceil(total ÷ max continuous) − 1, so a break is added between segments but not after the last one. Total break time = breaks × break length, and total elapsed = working hours + all break time. A stint shorter than one maximum segment needs no breaks.
Worked example
Worked example. A 12-hour stint with a 5-hour maximum and 30-minute breaks needs ceil(12 ÷ 5) − 1 = 3 − 1 = 2 breaks. That is 60 minutes (1:00) of breaks, so the total elapsed time is 12 + 1 = 13 hours.
Common mistakes
- Forgetting to add break time to the finish estimate — the breaks push out your total elapsed time.
- Treating the result as a legal limit — it is a planning guide, not the NHVR work/rest rules or your fatigue-management plan.
- Setting the maximum continuous hours too high — long unbroken stints are exactly what fatigue rules aim to prevent.
Frequently asked questions
Why is there no break after the last segment?
A break is only useful between spells of work. Once the final segment finishes the stint is over, so the formula subtracts one break: ceil(total ÷ max continuous) − 1.
Does this replace the NHVR work and rest limits?
No. It is a general planning guide only. Heavy-vehicle drivers must follow the National Heavy Vehicle Regulator work/rest limits and their operator's fatigue-management plan, which set legally required maximum work times and minimum rest breaks.
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Tip: Enter any known values to calculate the remaining results.
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