Time Calculator
A time calculator does arithmetic with clock times. It finds how many hours and minutes there are between two times, including shifts that run past midnight, and it adds or subtracts a duration from a clock time. Everything is converted to minutes after midnight, calculated, and converted back.
How to use the time calculator
- Choose: time between two times, or add or subtract time.
- Enter times in 24-hour hh:mm format, such as 09:15.
- Press Calculate to see the result and the working.
Formula
Worked example: 09:15 to 17:40
- What do you want?: Time between two times
- Start time (hh:mm): 09:15
- End time (hh:mm): 17:40
✓ Answer checked
8 hours 25 minutes
- In minutes
- 505
- In hours (decimal)
- 8.41667
Step-by-step working (3 steps)
Convert to minutes after midnight
Hours × 60 + minutes.
Subtract
End minus start.
Convert back
Divide by 60: whole hours and leftover minutes.
How this was checked
- ✓ Adding 8 h 25 min to 09:15 gives 17:40.
Frequently asked questions
How many hours from 09:15 to 17:40?
8 hours 25 minutes.
How do I calculate an overnight shift?
If the end time is earlier on the clock, add 24 hours to it before subtracting. 22:30 to 06:15 is 7 hours 45 minutes.
Can I use 12-hour times?
Use 24-hour times: 2:30 pm is 14:30.
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