Dates & Time

Time Adder (Add & Subtract HH:MM:SS Durations)

Add and subtract a list of durations in HH:MM:SS format for video splits, timesheets, or laps. It handles multiple rows, add or subtract per row, and day-rollover output.

How to use
  1. Enter each duration in HH:MM:SS.
  2. Set each row to add or subtract.
  3. Add more rows as needed.
Tip Click + on a row to switch it to subtract (−).
Total duration
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Total hours
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Total minutes
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Total seconds
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Active rows
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Date math uses your inputs as given; check time-zone and leap-year edge cases.
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Common questions

Can I subtract a duration from the total?

Yes. Each row has an add or subtract toggle, so you can mix additions and subtractions in one list.

What happens past 24 hours?

The total rolls over into days, so a sum above 24 hours shows the days plus the remaining hours, minutes, and seconds.

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