Time Duration Calculator
Calculate elapsed hours, minutes and seconds between two times or date-times.
Elapsed time
Both times are treated as occurring on the same day.
About the Time Duration Calculator
The Time Duration Calculator measures elapsed time between a start time and an end time. Results include total hours with remaining minutes and seconds, decimal hours and total seconds.
When dates are not included and the end time is earlier than the start time, the calculator treats the end as occurring on the following day. For example, 10:30 PM to 1:15 AM is 2 hours and 45 minutes.
Enable dates for shifts, projects, travel or events lasting longer than 24 hours. Date mode uses the selected calendar dates and can report any valid multi-day duration.
Seconds are supported for precise measurements. Calculations use date-only UTC arithmetic, so daylight-saving clock shifts and local timezone conversions do not alter the entered wall-clock values.
Key features
- Hours, minutes and seconds breakdown
- Decimal hours and total seconds
- Automatic midnight crossing
- Optional dates for multi-day durations
How to use
- 1Enter the start time and end time.
- 2Enable Include dates when the duration spans known calendar dates or exceeds 24 hours.
- 3Review the elapsed time breakdown, decimal hours and crossing explanation.
Frequently asked questions
- What happens when the end time is earlier than the start time?
- Without dates, the calculator treats the end time as occurring on the following day. With dates enabled, it follows the selected dates and rejects a reversed date-time range.
- Can the duration be longer than 24 hours?
- Yes. Enable Include dates and choose start and end dates. The hours result can then exceed 24.
- How are decimal hours calculated?
- The complete duration in seconds is divided by 3,600. For example, 2 hours and 30 minutes equals 2.5 decimal hours.
- Does the calculator include seconds?
- Yes. The time fields accept seconds, and the result includes both remaining seconds and total elapsed seconds.
- Is a daylight-saving transition applied?
- No. This tool compares the wall-clock times and calendar dates you enter without applying a timezone or daylight-saving adjustment.