Time Duration Calculator: Add and Subtract Hours and Minutes
Totalling several tasks, taking a break off a shift or finding what time it will be in 7 hours 45 minutes. Two calculators on this page do the arithmetic that hours and minutes make awkward, because there are 60 minutes in an hour, not 100.
Add and subtract hours and minutes
Enter durations like 1:30, 2h 15m, 45m or 1.5. The first line is your starting amount.
Add and subtract hours and minutes ·
Enter your numbers above and the result appears here.
How this was calculated
Add or subtract time from a clock time
What time is it 7 hours 45 minutes after 10:15 pm?
Add or subtract time from a clock time ·
Enter your numbers above and the result appears here.
How this was calculated
Why hours and minutes are hard to add by hand
Decimal arithmetic assumes ten of something makes the next unit, but minutes roll over at 60. Adding 1:45 and 2:30 as if they were decimals gives 3.75, but the correct answer is 4:15. The reliable manual method is to convert everything to minutes, add or subtract, then convert back.
Worked examples
Adding task times
Start with 3:45, add 2:30, add 1:15. In minutes: 225 + 150 + 75 = 450 minutes = 7 hours 30 minutes = 7:30 (7.50 decimal hours).
Subtracting a break
A 9:15 shift minus a 0:45 unpaid break: 555 − 45 = 510 minutes = 8:30.
What time will it be?
10:15 pm plus 7 hours 45 minutes: 22:15 + 7:45 = 30:00. Subtract 24 hours: 6:00, which is 6:00 am the next day.
Going backwards
What time did a 6.5-hour job that finished at 2:10 pm start? 14:10 minus 6:30 = 7:40 am.
Accepted formats
1:30 | 1 hour 30 minutes |
1h 30m or 1 hr 30 min | 1 hour 30 minutes |
45m | 45 minutes |
1.5 | 1.5 hours (1 hour 30 minutes) |
2h | 2 hours |
Results show hours:minutes, decimal hours, total minutes and, over 24 hours, days plus hours. Decimal hours are what most payroll tools want; the decimal hours converter explains the conversion in depth.
When to use which tool
- One shift with a start and end time: hours calculator.
- A whole week or pay period: time card calculator.
- Many separate durations to total: the first calculator on this page.
Hours and minutes in everyday tasks
Adding durations comes up more often than people expect: totalling a week of project tasks, adding travel time to a meeting, working out how long a flight and layover take, subtracting a lunch from a shift or checking how much overtime you did across several days. The principle is the same in each case: turn every duration into minutes, add or subtract, and turn the result back into hours and minutes.
Example, travel plan: a 2 hour 50 minute drive, a 45-minute stop, and a 1 hour 35 minute ferry add to 170 + 45 + 95 = 310 minutes = 5 hours 10 minutes. If you leave at 7:20 am, the second calculator on this page shows an arrival at 12:30 pm.
Time arithmetic cheat sheet
| Minutes | As hours:minutes | Decimal hours |
|---|---|---|
| 15 | 0:15 | 0.25 |
| 30 | 0:30 | 0.50 |
| 45 | 0:45 | 0.75 |
| 90 | 1:30 | 1.50 |
| 105 | 1:45 | 1.75 |
| 150 | 2:30 | 2.50 |
| 480 | 8:00 | 8.00 |
| 525 | 8:45 | 8.75 |
Need many more conversions? The minutes to decimal chart has every value from 0 to 59.
Common calculations people run here
| Task | Example | Result |
|---|---|---|
| Total a week of billable tasks | 2:30 + 1:45 + 3:15 + 0:50 | 8:20 |
| Subtract lunch from a shift | 8:45 - 0:30 | 8:15 |
| Add commute both ways | 0:42 + 0:48 | 1:30 |
| Overtime beyond 8 hours | 10:20 - 8:00 | 2:20 |
| Remaining time in a 40-hour week | 40:00 - 34:35 | 5:25 |
| Total two shifts | 6:40 + 5:50 | 12:30 |
Each of these can be done in the first calculator above. Use Subtract on the second line to take time away from the first.
Time zones, days and long durations
This calculator treats a day as exactly 24 hours (1,440 minutes). It does not know about time zones or daylight saving changes; if a task spans a clock change, adjust by an hour. Durations over 24 hours are shown both in total hours and as days plus hours, so 52:30 appears as 52:30 and 2d 4:30.
Frequently asked questions
How do I add hours and minutes?
Convert to minutes, add, and convert back: 2:45 + 1:30 is 165 + 90 = 255 minutes = 4:15. Or let the calculator do it.
How do I subtract time?
Convert to minutes and subtract. 5:10 minus 1:40 is 310 − 100 = 210 minutes = 3:30.
What is 1.5 hours in hours and minutes?
1 hour 30 minutes. The decimal .5 is half of 60 minutes.
Can the result be negative?
Yes. If you subtract more than you started with, the answer shows a minus sign, for example -0:30.
Does it work for time past 24 hours?
Yes. Totals over 24 hours are shown in hours and also as days plus hours.