Time duration calculator
From to is how long?
plus is?
minus is?
Durations as h:mm, h:mm:ss or decimal hours (2.75 = 2:45).
How to work out a duration
- Count the hours to the next midnight, add 24 hours for each full day between, then the time on the last day.
- Add or subtract minutes first; carry or borrow 60 minutes as 1 hour.
- Decimal hours: divide the minutes by 60. 2 h 45 min = 2 + 45 ÷ 60 = 2.75.
Durations in hours, minutes and seconds
| Duration | h:mm | Hours | Minutes | Seconds |
|---|---|---|---|---|
| 15 minutes | 0:15 | 0.25 | 15 | 900 |
| 30 minutes | 0:30 | 0.50 | 30 | 1,800 |
| 45 minutes | 0:45 | 0.75 | 45 | 2,700 |
| 1 hour | 1:00 | 1.00 | 60 | 3,600 |
| 1 h 30 min | 1:30 | 1.50 | 90 | 5,400 |
| 2 h 45 min | 2:45 | 2.75 | 165 | 9,900 |
| 8 hours | 8:00 | 8.00 | 480 | 28,800 |
| 24 hours | 24:00 | 24.00 | 1,440 | 86,400 |
| 1 week | 168:00 | 168.00 | 10,080 | 604,800 |
Hours worked in a shift, minus lunch: the hours calculator. A whole week: the time card calculator. Days rather than hours: the date calculator.
Frequently asked questions
How do you calculate the duration between two times?
Turn both into hours and minutes from the same starting point and subtract. 10:00 PM on March 1 to 6:30 AM on March 3 is 2 h (to midnight) + 24 h + 6 h 30 min = 1 day 8 h 30 min, or 32.50 hours.
How do you add hours and minutes?
Add the minutes, then the hours, and carry 60 minutes as 1 hour. 2:45 + 1:30: 45 + 30 = 75 minutes = 1 h 15 min, so 2 + 1 + 1 h = 4:15.
How do you subtract times?
Borrow 60 minutes from the hours when needed. 8:00 − 2:45: 8:00 is 7 h 60 min, minus 2 h 45 min = 5:15.
Does daylight saving time change the duration?
Yes, across the change: the night clocks spring forward lasts one hour less, and the night they fall back one hour more. This calculator counts real elapsed time in your own time zone, so it includes that hour.