Working out a duration from clock times is easy to get wrong when it crosses noon or midnight, or when you mix minutes with decimal hours (7 h 30 min = 7.5 h, not 7.3 h). This calculator handles both 12- and 24-hour clocks, so just pick the times.
How to use the Time Duration Calculator
- Start time
- End time
- Breaks
Results update as you type, and every field accepts the units shown in its menu.
How it works
Pick the start and end times and enter any break.
Inputs explained
| Field | What to enter |
|---|---|
| Start time | A clock time (hours and minutes) |
| End time | A clock time (hours and minutes) |
| Breaks | In min |
What each result means
- Elapsed time = mod([End time] – [Start time], 24)
- Duration = [Elapsed time] – [Breaks]÷60
- Decimal hours = [Duration]
- Total minutes = [Duration]×60
- Share of a day = [Duration]÷24×100
Formula
Duration = end time − start time (+ 24 h if the end is past midnight) − breaks
Decimal hours = hours + minutes ÷ 60
Worked example
Inputs: Start time: 09:15; End time: 17:45; Breaks: 30 min.
Results: Elapsed time = 8 h 30 min; Duration = 8 h 0 min; Decimal hours = 8; Total minutes = 480; Start (12-hour clock) = 9:15 AM; End (12-hour clock) = 5:45 PM; Share of a day = 33.3 %.
Frequently asked questions
How do I calculate time between two times?
Subtract the start from the end; if the result is negative, add 24 hours.
How many hours from 9:15 am to 5:45 pm?
8 h 30 min, or 8.5 hours.
How do I convert minutes to decimal hours?
Divide by 60. For example, 45 minutes is 0.75 h.