Time Duration Calculator
Enter a start and end time and press Calculate to get the duration in hours and minutes and as decimal hours, ready for a timesheet. Overnight shifts are handled automatically.
Time Duration Calculator
How to calculate time duration
- Convert each time to 24-hour format: 1:00 PM = 13:00, 9:30 PM = 21:30. Times from 12:00 AM to 12:59 AM become 00:00 to 00:59.
- Turn each into minutes after midnight: hours × 60 + minutes.
- Subtract the start from the end. If the result is negative, the period crosses midnight, so add 1,440 (the minutes in a day).
- Subtract any unpaid break, then divide by 60 for hours.
Example: 9:00 AM to 5:30 PM with a 30-minute lunch → 1,050 − 540 = 510 minutes, minus 30 = 480 minutes = 8 hours.
Minutes to decimal hours
Payroll systems usually need decimal hours, not hours and minutes.
| Minutes | Decimal | Minutes | Decimal | Minutes | Decimal |
|---|---|---|---|---|---|
| 5 | 0.08 | 25 | 0.42 | 45 | 0.75 |
| 10 | 0.17 | 30 | 0.50 | 50 | 0.83 |
| 15 | 0.25 | 35 | 0.58 | 55 | 0.92 |
| 20 | 0.33 | 40 | 0.67 | 60 | 1.00 |
Weekly timesheet tip
Add up each day's minutes first and convert to decimal hours once at the end. Rounding every day to two decimals and then adding can be off by a few minutes over a week.
Frequently asked questions
How do I calculate hours between two times?
Convert both times to minutes after midnight, subtract the start from the end, and divide by 60. From 8:45 AM (525 minutes) to 5:15 PM (1,035 minutes) is 510 minutes, which is 8 hours 30 minutes, or 8.5 hours.
How do I calculate an overnight shift?
If the end time is earlier than the start, add 24 hours to the end time before subtracting. A 10:00 PM to 6:30 AM shift is 8 hours 30 minutes. The calculator does this for you when both times are on the same date.
How do I convert minutes to decimal hours?
Divide the minutes by 60. 15 minutes = 0.25 hours, 30 minutes = 0.5, 45 minutes = 0.75, and 20 minutes ≈ 0.33. So 7 hours 45 minutes is 7.75 hours.
Does this account for daylight saving time?
No. It measures wall-clock time, so a night shift that spans a clock change will be one hour off from the true elapsed time. Adjust by hand on those two nights a year.
See also
- Date Calculator: Days between two dates, or add and subtract days from a date.
- Percentage Calculator: Percent of a number, percent change, and increase or decrease by a percent.
- Proportion Calculator: Solve A/B = C/D for the missing number, with steps.
Last updated: November 4, 2026