Time duration calculator

Choose your start and end time, enter any break you want to subtract, and select Calculate duration. The result includes days, hours, minutes and seconds, plus total minutes and decimal hours. Use optional dates for intervals longer than one day.

Same day or overnight?

Without dates, an end time earlier than the start is treated as the following day. For example, 23:30 to 01:15 is 1 hour 45 minutes. If the end clock time is equal to or later than the start but belongs to tomorrow, select End is next day. This lets 09:00 to 09:00 mean 24 hours instead of zero.

Include dates for longer intervals

Turn on Include start and end dates and select both dates. The calculator uses that exact calendar interval instead of assuming an overnight shift. It includes weekends and leap days. An end date and time before the start is rejected.

Duration = end date and time − start date and time − breaks

For clock times alone, convert each time to seconds: hours × 3,600 + minutes × 60 + seconds. Subtract the start from the end, adding 86,400 seconds when the end is on the next day.

Decimal hours are not hours and minutes

8 hours 30 minutes is 8.5 hours, not 8.30 hours. Divide the minutes by 60 before adding them to the hours. The calculator shows both formats so you can use the one your timesheet or planning document expects.

Subtract a lunch break or pause

A 09:00–17:30 interval with a 30-minute break gives 8 hours. Breaks must be nonnegative and cannot exceed the total interval. Decimal minutes are accepted and rounded to the nearest second.

Clock changes and time zones

This tool compares the calendar dates and clock times you enter, counting each day as 24 hours. It does not account for time zones, daylight saving changes or leap seconds. For real elapsed time across a clock change or between locations, use a calculator that asks for the relevant time zones. The timeanddate duration calculator guide explains this distinction.