Time Calculator

How to add or subtract time

Enter each time value in hours, minutes, and seconds, choose whether to add or subtract it, and this tool totals everything up automatically carrying over minutes into hours and seconds into minutes, just like a clock.

Real-world uses for adding and subtracting time

This calculator is built for anything that involves stacking up multiple durations totaling billable hours from several client calls, adding up segments of a video edit, tallying practice time logged across a week, or working out how much time is left in a project budget after subtracting hours already spent. Payroll and freelance invoicing are common cases: enter each block of time you worked (or each task), and get one final total instead of adding it up by hand.

How carrying works

Time doesn't work in base 10 60 seconds make a minute and 60 minutes make an hour, not 100. This calculator handles that conversion automatically: if your seconds add up to 90, it carries 1 minute and 30 seconds; if your minutes add up to 75, it carries 1 hour and 15 minutes. For example, adding 1h 45m to 2h 30m doesn't give you "3h 75m" it carries the extra 15 minutes into the hours column and shows 4h 15m.

What if the total goes negative?

Switch a row to subtract mode to remove time from the running total useful for figuring out how much time remains after deducting breaks, meetings, or time already spent. If the total goes negative (you've subtracted more than you added), the result displays as a negative duration, like "-1h 15m 0s", rather than wrapping around or showing an error.

Decimal hours vs. hours and minutes

The result box shows both formats: a clock-style total ("4h 15m 0s") and the same value as decimal hours ("4.2500 total hours"). Decimal hours matter for payroll and invoicing, since most systems calculate pay by multiplying decimal hours by an hourly rate rather than working in hours and minutes directly 4 hours 15 minutes is 4.25 hours, not 4.15.

FAQ

Can I add more than two times?
Yes click "+ Add Time" to add as many rows as you need.

Does this handle times over 24 hours?
Yes the total can exceed 24 hours; it isn't wrapped back to a clock time.

Why do I need decimal hours instead of just hours and minutes?
Payroll systems and invoicing software generally calculate pay by multiplying decimal hours by an hourly rate, so 4 hours 30 minutes needs to be entered or reported as 4.5, not 4:30. This calculator shows both formats so you can use whichever one you need.

Can I subtract a time that's larger than my total?
Yes the result will simply go negative and display with a minus sign, like "-0h 45m 0s", rather than showing an error.

Does it round the seconds?
No seconds are calculated exactly and only rounded for display when the total contains a fractional second, so the total stays accurate even with many rows.

Can I remove a row I added by mistake?
Yes click the button next to any row to remove it, and the total recalculates immediately.