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Time Duration Calculator

Add or subtract lengths of time entered as hours, minutes and seconds, and get a clean total in HH:MM:SS. It is the tool for stacking up durations rather than clock times: adding lap times, summing task lengths, working out total run time across several clips, or subtracting a break from a shift. Choose whether each row adds to or removes from the running total, and the calculator carries seconds into minutes and minutes into hours automatically so you never have to borrow by hand. It also shows the result as decimal hours, which is exactly what you need for timesheets and billing. Enter your values, pick add or subtract, and see the total instantly. Everything is computed in your browser with no accounts and no data leaving your device.

How to use Time Duration Calculator

  1. Enter each duration in hours, minutes and seconds.
  2. Choose whether to add or subtract each one.
  3. Read the total in HH:MM:SS and in decimal hours.

Frequently asked questions

Can I add several durations together?

Yes. You can combine multiple hours, minutes and seconds entries and it returns the running total.

What formats is the total shown in?

The total is shown both as HH:MM:SS and as decimal hours, which is handy for pay or logging.

Can I subtract time as well as add it?

Yes. The tool supports adding and subtracting durations to find the net time.

What is Time Duration Calculator?

Add or subtract lengths of time entered as hours, minutes and seconds, and get a clean total in HH:MM:SS. It is the tool for stacking up durations rather than clock times: adding lap times, summing task lengths, working out total run time across several clips, or subtracting a break from a shift.

Is Time Duration Calculator free to use?

Yes. Time Duration Calculator is completely free, with no sign-up and no usage limits.

Does Time Duration Calculator work in a web browser?

Yes. Time Duration Calculator runs in any modern web browser. There is nothing to download or install.

Is my data private with Time Duration Calculator?

Yes. Time Duration Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.