What happens if subtraction goes negative?

The result is shown with a minus sign in front of hh:mm:ss, and the total minutes/hours are negative too — so you can tell at a glance the second duration was larger.

Can I use this to add up work hours or timer durations?

Yes — enter each duration's hours, minutes, and seconds and add them together. For adding more than two durations, add the running total to the next duration.

Does this handle values over 59 minutes or seconds?

Minutes and seconds fields are capped at 59 for clarity, but you can enter any number of hours — the tool converts everything to total seconds internally before formatting the result.

Is my data sent anywhere?

No. All math runs locally in your browser — nothing is transmitted or stored.

TIME CALCULATOR

Add or subtract durations. Nothing leaves your browser.

Time 1

Hours

Minutes

Seconds

Time 2

Hours

Minutes

Seconds

Result (hh:mm:ss)03:45:00

Total minutes225

Total hours3.75

How to add or subtract time

1
Enter the first duration in hours, minutes, and seconds.
2
Choose to add or subtract.
3
Enter the second duration.
4
Read the result as hh:mm:ss, total minutes, and total hours.

Questions

What happens if subtraction goes negative?: The result is shown with a minus sign in front of hh:mm:ss, and the total minutes/hours are negative too — so you can tell at a glance the second duration was larger.
Can I use this to add up work hours or timer durations?: Yes — enter each duration's hours, minutes, and seconds and add them together. For adding more than two durations, add the running total to the next duration.
Does this handle values over 59 minutes or seconds?: Minutes and seconds fields are capped at 59 for clarity, but you can enter any number of hours — the tool converts everything to total seconds internally before formatting the result.
Is my data sent anywhere?: No. All math runs locally in your browser — nothing is transmitted or stored.