Time Duration Calculator
Find the exact hours and minutes between a start and end time.
Try an example
8h 30m
About this calculator
How This Time Duration Calculator Works
Enter a start time and an end time, and the calculator returns the duration between them in hours and minutes — including handling for durations that span past midnight.
Worked Example
From 9:00 AM to 5:30 PM is 8 hours 30 minutes.
Handling the Midnight Crossover
If the end time is earlier in the clock than the start time (like a 10:00 PM to 6:00 AM overnight shift), a straight subtraction gives a negative number, which isn't a valid duration. The calculator detects this and adds 24 hours to the difference, correctly treating the end time as falling on the next day. There's also a manual toggle for cases where the times happen to be equal or ambiguous but you know the shift crosses midnight.
Common Uses
Timesheet calculations, shift length, event or meeting duration, cooking or workout timing — anywhere you have a clock start and end time and need the elapsed time between them rather than a calendar date difference (for date-to-date spans, see the Date Calculator instead).
Worked example
From 9:00 AM to 5:30 PM is 8 hours and 30 minutes.
Frequently asked questions
How do I calculate a duration that crosses midnight?
Check "End time is the next day" — this adds 24 hours before subtracting, so an overnight shift like 10 PM to 6 AM correctly comes out to 8 hours instead of a negative number.
Does this account for time zones?
No — both times are treated as being in the same time zone. For a duration spanning time zones, convert both times to the same zone first.