About the Time Duration Calculator
Add or subtract hours, minutes and seconds, and convert the total between units.
Also known as: add time calculator, subtract time, duration adder, hours minutes seconds calculator.
How to use this calculator
- Enter hours, minutes, seconds, operation and the other fields.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
Convert both to seconds, combine, then convert back
Worked example
Using the values pre-filled in the calculator above:
- Hours = 2
- Minutes = 45
- Seconds = 0
- Operation: Add
- Hours = 1
- Minutes = 30
- Seconds = 0
the calculator returns:
- Result: 4 h 15 min 0 s
- Total hours: 4.25
- Total minutes: 255
- Total seconds: 15,300