Time Duration Calculator

Find the difference between two times, or add a duration to a date

Difference
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About this Calculator

The Time Duration Calculator finds the span between two points in time and can shift a date by a chosen amount. Use it to measure project lengths, count down to events, or compute a future/past time by adding days, hours, or minutes. Everything runs locally in your browser — private and instant.

Privacy Note: All calculations are performed locally in your browser. No data is ever sent to a server or third party.

Time Duration Calculator FAQ

How is the difference calculated?
It subtracts the start time from the end time and breaks the result into whole days, remaining hours, and remaining minutes.
Can I subtract time instead of adding?
Enter a negative amount in the "Add to start" field to move backward in time.
Does it handle different time zones?
The inputs use your device's local time zone. For cross-time-zone math, convert to a common zone first.