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Time Calculator

Add two durations together or subtract one from the other, in hours, minutes and seconds. The answer comes back in clock format and also as decimal hours — the form timesheets and invoices usually want, where 2 hours 45 minutes has to be entered as 2.75 rather than 2.45.

Total time

4:15:00

In hours
4.25
In minutes
255
In seconds
15,300
Written out
4h 15m 0s

Nothing is uploaded — this tool runs inside your browser, so your files never leave your device.

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Why use this tool

  • Add or subtract two durations in hours, minutes and seconds
  • Answer in clock format plus decimal hours for timesheets
  • Also given in total minutes and total seconds
  • Negative results are shown honestly rather than flipped

How it works

  1. 1Choose whether to add or subtract.
  2. 2Enter both durations in hours, minutes and seconds.
  3. 3Use the decimal hours figure for timesheets and invoices.

Time Calculator — frequently asked questions

Divide the minutes by 60. 45 minutes is 0.75 hours, so 2 hours 45 minutes is 2.75 — not 2.45. Writing it as 2.45 is the single most common timesheet error, and it undercharges by 18 minutes.

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