Time & dates
Time duration calculator
Calculate elapsed hours and minutes from a start time to an end time, including overnight periods. Also see the result as decimal hours.
How to calculate it
Each time is converted to minutes after midnight. Subtracting the start from the end gives the total minutes. Divide by 60 to convert to decimal hours, or use the whole-number hours and remaining minutes for a clock-style duration.
Worked examples
| Example | Working | Answer |
|---|---|---|
| 09:00 to 17:30 | 510 minutes ÷ 60 | 8h 30m |
| 22:00 to 06:00 | End time is next day | 8h 0m |
| 12:15 to 13:00 | 45 minutes ÷ 60 | 0h 45m |
| 09:00 to 09:00 | Equal times | 0h 0m |
Frequently asked questions
How does overnight calculation work?
When the end time is earlier than the start time, it is treated as the following day. For example, 22:00 to 06:00 is eight hours.
Can I calculate periods over 24 hours?
No. This tool covers periods under 24 hours. Equal start and end times mean zero hours. For longer periods, calculate full days separately.
Are breaks or time zones included?
No. The result is a simple clock-time difference. Subtract breaks separately. It does not adjust for time zones or daylight-saving transitions.
Method: standard arithmetic. Examples are illustrative. How our calculators work.