Time Calculator
Add or subtract two durations in hours, minutes, and seconds. See the result in h:m:s as well as total minutes and seconds.
Duration 1
Duration 2
Add or subtract two durations. A negative result means duration 2 was larger than duration 1.
How to use this calculator
Enter Duration 1 and Duration 2 in hours, minutes, and seconds, then choose Add or Subtract. The result appears in h:m:s plus total minutes and seconds.
How time math works
The calculator converts each duration to total seconds, performs the operation, then converts back to hours, minutes, and seconds. This avoids the confusion of carrying over 60s and 60m by hand.
Worked example
2h 30m plus 1h 45m equals 4h 15m — or 255 minutes, or 15,300 seconds.
For clock-in/out time, see the hours calculator.
Frequently asked questions
How do I add two times together?
Enter each duration as hours, minutes, and seconds, then choose Add. The calculator converts both to seconds, adds them, and shows the total in h:m:s, minutes, and seconds.
How do I subtract time?
Choose Subtract to find the difference between two durations. If the second is larger, the result is shown as a negative duration.
Can I total work hours with this?
This adds durations, not clock times. To total a shift from clock-in to clock-out, use the hours calculator; for a whole week, use the time card calculator.
How many seconds are in an hour?
There are 3,600 seconds in an hour and 60 in a minute. The calculator uses these to convert everything to seconds before adding or subtracting.