How to calculate hours between two times
The hours between two times are the end time minus the start time, with any unpaid break taken off. If the end time is earlier than the start, add 24 hours because the shift crosses midnight.
Skip the maths and use the time duration calculator
The formula
Duration = end time − start time − break. Add 24 hours if the end time falls the next day.
Step by step
- Convert both times to the 24-hour clock.
- Subtract the start time from the end time.
- Add 24 hours if the answer is negative.
- Subtract unpaid break minutes, then convert to decimal hours if you are paid by the hour.
Worked example
09:15 to 17:45 with a 30-minute unpaid break
- 17:45 − 09:15 = 8 hours 30 minutes
- 8 hours 30 minutes − 30 minutes = 8 hours
The paid time is 8 hours, or 8.00 decimal hours.