Time Calculator – Add and Subtract Durations

What you enter is processed only in this browser and is never sent to a server. How it works

How to add and subtract time

Choose an input format and enter one duration per line. In hours:minutes mode, 1:35 plus 0:48 equals 2:23:00. In minutes:seconds mode, the same input equals 0:02:23. Choose the right format for work durations, video lengths or workout intervals.

Input rules and calculation limits

Hours:minutes mode also accepts hours:minutes:seconds. The final minutes and seconds must have two digits from 00 to 59. The first unit accepts up to 9 integer digits and may exceed 24. Blank lines are ignored. The limit is 1,000 lines and 50,000 characters. Prefix a duration with a minus, such as -0:10, to subtract it. Results use hours:minutes:seconds; total minutes are rounded to four decimal places.

Durations and clock times

This tool adds elapsed durations. It does not infer a shift from 23:00 to 01:00, date boundaries, breaks, time zones or daylight saving time. It does not interpret 1:30 as 1.30 hours. Decimal-hour input and leap seconds are not supported.

Frequently asked questions

What happens when the total exceeds 24 hours?

The result stays a duration instead of becoming a date. A result of 25:30:00 means 25 hours and 30 minutes, which suits long tasks or several videos.

Can the total be negative?

If you subtract more than you add, a minus appears before the whole duration, such as -1:00:05. Signs on individual minute or second components are not supported.