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Add or subtract hours, minutes, and seconds.
Updated
Add or subtract spans of time, or find the duration between a start and end time — handy for timesheets, cooking, and scheduling. Everything calculates instantly in your browser.
Runs entirely in your browser — nothing is uploaded.
A time calculator does arithmetic on clock times and durations, which ordinary calculators get wrong because minutes and seconds roll over at 60 rather than 100. This one has two modes. Add or Subtract takes two spans entered as hours, minutes, and seconds, converts each to total seconds, applies the operation, and splits the answer back into hours, minutes, and seconds, so entering 90 minutes is fine and comes back as 1h 30m. Hours are not capped, so totals beyond 24 hours display as is, and if you subtract a larger span from a smaller one the result is shown with a minus sign. Duration takes a start and end clock time in hours and minutes and gives the gap between them; if the end is earlier than the start, it assumes you crossed midnight and adds a day. Results update as you type, values are whole numbers, and no dates or time zones are involved. Everything runs in your browser.
Yes — totals can exceed 24 hours (e.g. a full timesheet), shown as total hours, minutes, and seconds.
Yes — in duration mode, an end time earlier than the start is treated as the next day.
No. Fields take whole numbers, and a decimal is truncated, so 7.5 becomes 7. Enter 7 in the hours field and 30 in the minutes field instead. Values above the usual range are fine and are normalized, so 90 minutes is treated as 1 hour 30 minutes.