Time Duration Calculator
Find the hours and minutes between two times of day.
How time duration works
Time duration is the elapsed time between two times of day. Enter a start time and an end time; the calculator returns the difference in hours and minutes.
When the end time is earlier than the start time, the interval crosses midnight — for example 22:30 to 01:15 is 2 hours 45 minutes.
This calculator measures plain clock time only. It does not apply business hours, holidays or timezone conversions.
The formula
Duration = End − Start (add 24 hours when crossing midnight)
Subtract the start time from the end time in minutes. If the end is earlier than the start, add 24 hours (1440 minutes) to account for the midnight crossing.
Worked example
22:30 to 01:15
From 22:30 to midnight is 1 hour 30 minutes, and from midnight to 01:15 is 1 hour 15 minutes — 2 hours 45 minutes in total (165 minutes).
Frequently asked questions
What happens when the times cross midnight?
The calculator automatically adds 24 hours, so 22:30 to 01:15 is treated as 2 hours 45 minutes, not a negative duration.
Does this use 12-hour or 24-hour time?
Times are entered in 24-hour format (HH:MM), so 1:15 PM is entered as 13:15. This avoids AM/PM ambiguity.
Does it account for business hours?
No. This is plain elapsed clock time. If you need working-hours duration or timezone handling, that is beyond this tool's scope.
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