Time Duration Calculator

Enter a start time and an end time. The calculator shows the gap as H:MM:SS, spells it out in hours, minutes, and seconds, and also gives you the total seconds, total minutes, and total hours.

Tick it whenever the end time lands on the next day. The calculator adds 24 hours to the clock-time difference. An earlier end can represent an overnight shift, the same start and end becomes a 24-hour duration, and a later end on the next day can produce 32 hours, for example 8:00 AM to 4:00 PM. It has no date or timezone input, so it does not model daylight saving time.

An end time earlier than the start gives a negative duration, so the calculator waits for valid input instead of showing a wrong number. Tick the crosses midnight box, or swap the two times.

Yes. The time fields have a seconds slot, so you can enter values like 9:00:30 AM and measure a range down to the second.

H:MM:SS breaks the duration into hours, minutes, and seconds, so 2:30:00 means 2 hours and 30 minutes. Total minutes states the same span as one number, 150 in that case, which is easier to drop into billing or a spreadsheet.