A time duration calculator finds the exact elapsed time between two points in time, including both the date and time components. It is useful for calculating work hours, event durations, travel times and any situation where you need to know how much time has passed between two specific moments.

1. Enter the start date and time.
2. Enter the end date and time.
3. Click Calculate to see the duration in hours, minutes and seconds.

Start: 9:00 AM, End: 5:30 PM same day.
Duration: 8 hours 30 minutes (30,600 seconds)

The result is always positive — the calculator uses the absolute difference between the two times. If the end time is before the start time on the same day, the calculator assumes the end time is on the following day if the dates are the same.

• Forgetting to set the correct date when the duration spans midnight.
• Confusing 12-hour and 24-hour time — this calculator uses 24-hour format.

Can I calculate duration across multiple days?

Yes. Set different start and end dates. The calculator handles durations of any length.

Does this account for time zones?

No. Both times are treated as being in the same time zone. For cross-timezone calculations, use the Time Zone Converter.