Time Duration Calculator

Calculate elapsed time between two clock times, including an overnight finish.

Enter your values, then select Calculate.
Finish − start − break = duration
Finish − start − break = duration. Use the guide below to understand the assumptions.

How to use the time duration calculator

  1. Start time: Choose the starting time, using the same local time zone.
  2. End time: Choose the finishing time. An earlier time is treated as the next day.
  3. Unpaid break (minutes): Minutes to subtract from the elapsed duration.
  4. Select Calculate to see the result. Change any input and calculate again to compare.

Worked example

09:00 to 17:30 minus 30 minutes is 8 hours.

Formula and assumptions

Finish − start − break = duration.

Assumes at most 24 hours, with identical start/end meaning zero. Does not account for daylight-saving transitions.

Common questions

Why might my result differ from another estimate?

Assumes at most 24 hours, with identical start/end meaning zero. Does not account for daylight-saving transitions. Keep the same inputs and rounding when comparing tools.

Are my entries saved?

No. Calculations run on your device. Reloading or closing this page may clear your entries.