Time Duration Calculator
Work out how long a period lasts from a start time and an end time, including overnight spans.
Quick answer: enter your details below and click Calculate — your result appears instantly, right here in your browser. Nothing you enter is uploaded or stored.
T
Calculators
Enter your details below.
How to use
- Enter the start time as hours and minutes.
- Enter the end time as hours and minutes.
- Press Calculate to see the duration in hours and minutes.
About this tool
Enter a start time and an end time in hours and minutes and the calculator finds the difference. If the end time is earlier than the start time it assumes the period runs overnight and adds 24 hours, so a shift from evening to morning still comes out right.
Frequently asked questions
How do overnight periods work?
If the end time is earlier than the start time, 24 hours are added to the end time before subtracting, so 22:30 to 06:45 gives 8 hours 15 minutes.
What time format should I use?
Use 24-hour hours (0 to 23) and minutes (0 to 59) for both times.