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
The calculator converts both times to minutes after midnight and finds the difference. It shows the result in hours and minutes, and in decimal hours for use in timesheets. If you already know a duration such as 7:45, use the decimal hours calculator to convert it directly.
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 |
| 23:45 to 00:15 | End time is next day | 0h 30m |
| 08:30 to 16:00 | 450 minutes ÷ 60 | 7h 30m |
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.
How do I convert decimal hours to hours and minutes?
Multiply the fractional part by 60. For example, 7.5 decimal hours is 7 hours plus 0.5 × 60 = 30 minutes, giving 7h 30m.
How do I add up several time entries?
Calculate each duration separately with this tool, convert each result to decimal hours, then add the decimal hours together. Convert the total back to hours and minutes if needed.
Method: standard arithmetic. Examples are illustrative. How our calculators work.