Hours Calculator
Hours worked between a clock-in and clock-out, minus breaks, in decimal hours for payroll.
Your shift
An end time earlier than the start is read as an overnight shift.
No rounding (the exact minutes worked).
This works out how many hours and minutes fall between two times, with or without a break deducted.
It handles overnight shifts and gives the result in decimal hours for payroll.
Working out hours between two times
Finding hours between two times is subtraction, with two complications that catch people out.
The first is that minutes are base 60. From 9:15 AM to 5:30 PM is 8 hours 15 minutes, and for payroll that is 8.25 decimal hours, not 8.15.
The second is overnight shifts. Subtracting 10:00 PM from 6:00 AM gives a negative number, because the end time is numerically smaller. The fix is to add 24 hours to the end time first: 30:00 − 22:00 = 8 hours.
Any shift crossing midnight needs the 24-hour adjustment, or the subtraction returns a negative duration.
What to enter
- Start and end time
- In 12-hour or 24-hour format. The 24-hour clock avoids all AM/PM ambiguity.
- Break duration
- Deducted from the total. Unpaid meal breaks come off; short paid breaks do not.
- Output format
- Hours and minutes, total minutes, or decimal hours.
Common shift lengths
- 8 hours minus a 30-minute lunch
- 8.5 hours elapsed, 8.0 paid. The standard office day.
- 12-hour shift minus 30 minutes
- 11.5 paid hours. Common in healthcare and manufacturing.
- Half day
- 4 hours, usually with no break deduction.
- Full-time year
- 2,080 hours: 40 hours a week for 52 weeks.
What this assumes
Shifts crossing midnight need the end time advanced by 24 hours, or the result is negative.
Whether a break is paid depends on its length and on state law, so the deduction is a choice rather than automatic.
How to calculate hours between two times
Convert both times to minutes, subtract, then convert the answer back.
- overnight
- Add 1,440 minutes (24 hours) to the end time first
- decimal hours
- What payroll systems expect
Convert both times to 24-hour format. 5:30 PM becomes 17:30. This removes AM/PM confusion entirely.
Convert to total minutes. 17:30 is 1,050 minutes; 9:15 is 555.
Subtract, adding 24 hours if the shift crosses midnight. 1,050 − 555 = 495 minutes. For an overnight shift, add 1,440 to the end first.
Convert back and deduct breaks. 495 ÷ 60 = 8 hours 15 minutes, or 8.25 decimal hours. Then subtract any unpaid break.
See a worked example: a day shift and a night shift
- Day
- 9:15 AM to 5:30 PM
- Night
- 10:00 PM to 6:00 AM
Day: 1,050 − 555 = 495 minutes = 8 hours 15 minutes, or 8.25 decimal.
Night: naive subtraction gives 6:00 − 22:00 = −16 hours, which is obviously wrong.
Add 24 to the end: 30:00 − 22:00 = 8 hours.
With a 30-minute unpaid break, the day shift pays 7.75 hours and the night shift 7.5.
8.25 hours and 8.00 hours
Frequently asked questions
Add 24 hours to the end time, then subtract. A 10:00 PM to 6:00 AM shift is 30:00 − 22:00 = 8 hours.
Without that, the subtraction gives a negative result. Any tool used for shift work has to handle this case.
Divide the minutes by 60. 15 minutes is 0.25, 30 is 0.50, and 45 is 0.75.
8 hours 15 minutes is 8.25, not 8.15. Payroll systems expect decimals, and this conversion is where hours quietly go missing.
If it is unpaid, yes. Under federal rules, bona fide meal periods of 30 minutes or more are generally unpaid and excluded from hours worked.
Short breaks under about 20 minutes are generally paid and should not be deducted. State rules vary and can be more generous.
2,080 for full-time: 40 hours a week for 52 weeks. It is the standard basis for converting between salary and hourly pay.
That assumes paid time off. If your leave is unpaid, your actual hours are lower.
Eighty hours across nine days in a two-week period: eight nine-hour days, one eight-hour day, and one day off.
It gives every other Friday off without reducing hours. The workweek is usually defined to start mid-Friday so the arrangement does not trigger overtime.
Usually rounding. Many payroll systems round to the nearest quarter hour, which is permitted provided it is neutral over time.
The other common cause is break deduction. Check whether your breaks are being treated as paid or unpaid, since the assumption differs between employers.
Problems people actually run into
Subtracting an overnight shift directly
6:00 AM minus 10:00 PM gives a negative number, and a tool that does not handle it will either error or report nonsense.
Add 24 hours to the end time whenever it is numerically earlier than the start. It is the whole fix.
Reporting 8.15 for 8 hours 15 minutes
Minutes are sixtieths, not hundredths. 15 minutes is 0.25 of an hour, so the correct figure is 8.25.
The error is small per day and consistent, which is what makes it add up. Divide minutes by 60 every time.
Results are estimates for general information only and are not professional financial, medical, or legal advice. Read our full disclaimer.
Last updated: September 4, 2026