How to use the hour calculator
- Pick 12-hour (AM/PM) or 24-hour time. In 12-hour mode, choose AM or PM next to each box, or type it, as in
5:30 pm. - Type the start time. Short forms work:
9is 9:00 and845is 8:45. - Type the end time. The result updates as you type.
- Read the time difference as hours and minutes, decimal hours or total minutes. Use the swap button if you entered the times the wrong way round.
Calculating time between two times by hand
Clock time is easiest to subtract in 24-hour form, where 1:00 PM is 13:00 and 11:30 PM is 23:30. Then:
- Subtract the start minutes from the end minutes. If the end minutes are smaller, borrow 60 minutes from the end hour.
- Subtract the start hour from the end hour.
- If the hours come out negative, the period crosses midnight: add 24 hours.
Example: 8:45 AM to 3:10 PM is 15:10 − 8:45. Borrowing gives 14:70 − 8:45 = 6 hours 25 minutes. To get decimal hours, divide the minutes by 60: 25 ÷ 60 = 0.42, so 6.42 hours. To count minutes between two times instead, multiply the hours by 60 and add the minutes: 6 × 60 + 25 = 385 minutes.
How many hours between common start and end times
The table below is calculated with the same engine as the tool. The figures are elapsed time; any unpaid break comes off separately.
| Times | Hours and minutes | Decimal hours |
|---|---|---|
| 9:00 AM to 5:00 PM | 8 hours | 8.00 |
| 8:00 AM to 5:00 PM | 9 hours | 9.00 |
| 7:00 AM to 3:00 PM | 8 hours | 8.00 |
| 7:00 AM to 7:00 PM | 12 hours | 12.00 |
| 10:00 PM to 6:00 AM (overnight) | 8 hours | 8.00 |
Overnight shifts
When the end time is earlier on the clock than the start time, this time difference calculator assumes the end is the next day. A night shift from 11:00 PM to 7:30 AM is 8 hours 30 minutes, not a negative number. Periods longer than 24 hours, such as a 30-hour on-call stretch, are better added up as separate durations in the time calculator.
Elapsed time versus hours worked
The total hours here are simply the clock difference. For pay, what counts is hours worked: under federal rules a bona fide meal period, ordinarily 30 minutes or more with you fully relieved of duty, is not work time (29 CFR 785.19), while short rest breaks of about 5 to 20 minutes are (29 CFR 785.18). To subtract an unpaid lunch for each day and total a week, use the hours worked calculator. If your schedule is written in 24-hour time, the military time converter shows the 12-hour equivalent.