Date & time·Duration
Time Duration Calculator
Find elapsed time between two clocks, optionally across midnight. Fully client-side — no account, uploads, or remote storage.
Added Apr 18, 2026
Input
Result
Enter a value for mode to see your result.
How it works
Calculates the duration between two clock times, or converts a given hours/minutes/seconds combination into its total equivalents. Useful for time-tracking, scheduling, and sports timing.
Step by step
- 01Choose 'between two clock times' to find elapsed time between a start and end.
- 02Or choose 'add hours/minutes/seconds' to convert a raw duration.
- 03Enter times in HH:MM or HH:MM:SS format (24-hour clock).
- 04If the end time is before the start time, the tool assumes the period crosses midnight.
Examples
Working hours 09:00 to 17:30
17:30 − 09:00 = 8 hours 30 minutes.
Inputs
- Mode:
- between
- Start time:
- 09:00
- End time:
- 17:30
Result
- Duration:
- 8h 30m 0s
- Total hours:
- 8.5 hours
- Total minutes:
- 510 minutes
Convert 2h 45m 30s
2×3600 + 45×60 + 30 = 9,930 seconds = 165.5 minutes.
Inputs
- Mode:
- add
- Hours:
- 2
- Minutes:
- 45
- Seconds:
- 30
Result
- Duration:
- 2h 45m 30s
- Total minutes:
- 165.5 minutes
Frequently asked questions
What if the end time is before the start time?
The calculator assumes the period spans midnight. For example, 23:00 to 01:00 is calculated as 2 hours, not −22 hours.