Time Duration Calculator
Work out how long a shift, flight or activity lasted between two clock times — including periods that run past midnight — with optional break time removed.
Result
Enter your values and select Calculate to see the result.
How to use this calculator
- Enter the start and end times using the 24-hour or 12-hour picker your browser shows.
- If the end time is earlier than the start time, the period is assumed to end the next day.
- Optionally enter a break in minutes to subtract, for example an unpaid lunch break.
Formula
duration = end − start
If the end time is earlier than the start time, 24 hours are added: duration = end + 24 h − start.
Any break is then subtracted. Decimal hours are total minutes ÷ 60, which is the format most timesheets and payroll systems use.
Worked example
An overnight shift
Start 22:30, end 06:15 the next morning, with a 30-minute break.
06:15 is earlier than 22:30, so the shift crosses midnight: 7 hours 45 minutes. Minus the break: 7 hours 15 minutes, or 7.25 decimal hours.
Assumptions and limitations
- Durations are limited to less than 24 hours. For longer periods, use the Date Difference calculator.
- Daylight-saving clock changes during the period are not taken into account.
- If the start and end times are the same, the duration is zero.
Frequently asked questions
How do I convert minutes to decimal hours?
Divide the minutes by 60. For example 45 minutes is 0.75 hours, so 7 hours 45 minutes is 7.75 hours.
What if my shift is exactly 24 hours?
Equal start and end times give zero here. Use the Date Difference calculator with dates for periods of 24 hours or more.