Time Duration Calculator
Add or subtract durations written as hours, minutes and seconds. Work with recordings or task times that can run longer than a single day.
- Add and subtract HH:MM:SS durations
- Keep hours beyond 24
- Read the result as total seconds
Enter durations, not clock times
Use hours:minutes:seconds for each input. The values represent elapsed time, so 25:00:00 is a valid duration rather than a time of day.
Keep minute and second fields valid
Minutes and seconds must each be between 00 and 59. Carry larger amounts into the next field before entering them.
Read negative differences
Subtracting a longer duration from a shorter one produces a negative result. The sign describes the whole duration.
Combine recording segments
Add segment lengths to estimate a combined timeline. Overlaps, crossfades and playback-speed changes need to be accounted for separately.
Duration Calculator FAQs
No. Hours are kept as elapsed hours rather than a clock reading.
No. Use date tools for calendar intervals; this page handles fixed durations.
The sum is 02:15:30, or 8,130 seconds. Enter the two values and select add. Hours can exceed 24, so long recording schedules remain durations rather than wrapping to clock time. This tool does not calculate intervals between calendar dates.