Can I calculate a duration that crosses midnight?

Yes, tick "End time is next day" if the end time falls after midnight relative to the start time.

Time Calculator

Add or subtract time, or find the duration between two times

Add or Subtract Time

Start Time

Hours

Minutes

Seconds

Operation

Result Time 09:00:00

Time Difference

Start Time

End Time

End time is next day

Duration 8h 30m 0s

What is the Time Calculator?

The Time Calculator has two modes: adding or subtracting a duration (hours, minutes, seconds) from a starting time, and finding the exact duration between two times of day. It's useful for scheduling, timesheets, and working out shift lengths.

How to Use It

To add or subtract time: enter a start time, the hours/minutes/seconds to apply, choose Add or Subtract, and the result appears instantly.
To find a duration: enter a start and end time in the second section. Tick "End time is next day" if the end time is after midnight relative to the start.

Frequently Asked Questions

Yes — tick "End time is next day" in the Time Difference section if your end time falls after midnight relative to the start time (for example, a night shift from 10 PM to 6 AM).

Yes, the Add/Subtract tool wraps around a 24-hour clock automatically, so subtracting past midnight rolls back to the previous day's time.