Date & Time Calculators
Time Calculator
Add or subtract time durations, or calculate the exact duration between a start and end time.
About the Time Calculator
A time calculator makes working with hours, minutes and seconds effortless. Use it to add up logged work hours, subtract a break from a shift, or measure the duration between a start and end time.
Switch between the add, subtract and duration modes and the tool returns a clean hh:mm:ss result along with the totals in minutes and seconds.
How to use the Time Calculator
- Pick a mode: Add time, Subtract time or Duration.
- Enter the hours, minutes and seconds (or start and end times).
- Click Calculate.
- Read the result in hh:mm:ss and total units.
How the calculation works
Convert everything to seconds → add or subtract → convert back to hh:mm:ss
Example
Adding 2 h 45 m and 1 h 30 m gives 04:15:00 — that is 255 total minutes.
Frequently asked questions
Yes, the calculator handles any total and simply reports the combined hours without wrapping to a clock.
Enter a start and end time and it returns the elapsed time, rolling past midnight if the end time is earlier.
Yes, leave the other fields at zero and the result still shows the equivalent minutes and seconds.
In subtract mode, if the second duration is larger the result is shown as a negative duration.