Date & time · Durations

Time calculator

Add or subtract two durations, or find the elapsed time between two clock times.

Mode

Duration A

Duration B

Result
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Rough sheet

step-by-step
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How time durations are calculated

Adding or subtracting durations combines hours, minutes, and seconds separately, then carries over any overflow (60 seconds becomes 1 minute, 60 minutes becomes 1 hour) to produce a normalized result. When finding elapsed time between two clock times, the calculator accounts for durations that cross midnight by treating the later time as occurring on the following day when needed.

Frequently asked questions

Yes, when finding elapsed time between two clock times, the calculator automatically accounts for the case where the end time is on the next day.

Yes, "Duration" mode lets you add or subtract two hour/minute/second durations directly.