Time Calculator
Two modes: add or subtract durations (hours, minutes, seconds), or calculate the elapsed time between a start and end clock time.
Time A
Add
Time B
Result
2h 15m 00s
Total seconds
8,100 s
How it works
Add mode: convert each duration to seconds, add or subtract, then format back. Difference mode: convert both clock times to seconds since midnight, subtract end − start, and handle the next-day rollover for overnight ranges.
Frequently asked
- How do I add hours and minutes?
- Enter both durations and the calculator returns the total. Switch the operator to subtract for the difference.
- How do I calculate hours between two times?
- Use Difference mode. Enter the start and end clock time. If the end is earlier, the calculator assumes it is the next day.
- Can I use 12-hour or 24-hour formats?
- Both. Type 09:00 or 9:00 AM in either field. The calculator parses both.
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