Time Calculator
Add or subtract two durations in hours, minutes, and seconds.
Duration 1
Duration 2
Try an example
3h 45m 0s
About this calculator
How This Time Calculator Works
Enter two durations in hours, minutes, and seconds, choose to add or subtract, and the calculator returns the combined duration.
Worked Example
Adding 2h 30m to 1h 15m gives 3h 45m total.
How the Math Works
Each duration is converted to total seconds first (hours × 3600 + minutes × 60 + seconds), added or subtracted as plain numbers, then converted back into hours, minutes, and seconds for display — this avoids the awkward carrying/borrowing that direct hour/minute/second arithmetic would otherwise require (like 45 minutes + 30 minutes needing to "carry" into an extra hour).
Time Calculator vs. Time Duration Calculator
These solve different problems. This calculator combines two standalone durations (like "2h30m of work plus 1h15m of overtime"). The Time Duration Calculator instead finds the elapsed time between two clock times (like "9:00 AM to 5:30 PM"). Use whichever matches what you actually have: two lengths of time, or two points in the day.
Worked example
Adding 2h 30m to 1h 15m gives 3h 45m total.
Frequently asked questions
What happens if I subtract a larger duration from a smaller one?
The result is negative, shown with a minus sign — useful for checking whether a duration fits within a limit, or how far over/under a target it is.
How is this different from the Time Duration Calculator?
The Time Duration Calculator finds the elapsed time between two clock times (like 9:00 AM to 5:30 PM). This calculator adds or subtracts two standalone durations (like 2h30m + 1h15m), not clock times.