Time Calculator

Add or subtract a duration from any time, or measure the hours and minutes between two times — overnight shifts included.

Add / subtract time

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Duration between two times

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How it works

Every time becomes “minutes since midnight” — 09:30 is 570. Adding or subtracting a duration is plain addition, wrapped with modulo 1440 (the minutes in a day) so 23:30 plus an hour correctly becomes 00:30, flagged as the next day. For durations, the end time minus the start time gives the span; if the end is earlier, it’s treated as the next day, so 22:00 to 02:00 is a 4-hour overnight shift, not a negative number.