worldofcalcsTime Duration Calculator
Duration
8 h 45 min
Decimal hours
8.75
Total minutes
525
How do you calculate time between two times?
Convert both times to minutes after midnight, subtract, and convert back to hours and minutes. If the end time is earlier than the start, such as a night shift from 10 pm to 6 am, add 24 hours. This calculator does that, gives decimal hours for timesheets and billing, and can add or subtract hours and minutes from a time.
Time formulas
Duration = end − start (+ 24 h if the end is earlier) · Decimal hours = hours + minutes ÷ 60
Work in minutes to avoid mistakes: 9:30 is 570 minutes after midnight and 18:15 is 1,095.
Good to know
- 15 minutes is 0.25 hours, 30 minutes is 0.5 and 45 minutes is 0.75. Don't write 8 h 45 min as 8.45 hours.
- On a 12-hour clock, 12:00 noon is 12 PM and midnight is 12 AM; the 24-hour clock avoids the confusion.
- India uses a single time zone, IST, 5 hours 30 minutes ahead of UTC.
- For durations across several days, use the date difference calculator.
- To add up a whole week of shifts with breaks and overtime, use the time card calculator.
Worked examples
- From 09:30 to 18:15: 1,095 − 570 = 525 minutes = 8 h 45 min
- As decimal hours: 8 + 45 ÷ 60 = 8.75 hours
- Night shift from 22:00 to 06:00: 360 + 1,440 − 1,320 = 480 minutes = 8 hours
- 22:30 plus 3 h 45 min is 02:15 the next day
Minutes as decimal hours
For timesheets and billing.
| Minutes | Decimal hours |
|---|---|
| 5 | 0.08 |
| 6 | 0.1 |
| 10 | 0.17 |
| 12 | 0.2 |
| 15 | 0.25 |
| 20 | 0.33 |
| 30 | 0.5 |
| 40 | 0.67 |
| 45 | 0.75 |
| 50 | 0.83 |
Decimal hours = minutes ÷ 60.