How to calculate hours between two times
Convert both clock times to minutes after midnight. Subtract start from end. If the end is earlier on the clock — 10:00 PM to 6:00 AM — add 24 hours to the end first. Then subtract unpaid break minutes.
Example: 10:00 PM is 22:00. 6:00 AM the next day is 6:00 plus 24 hours = 30:00. 30 − 22 = 8 hours. A 30-minute unpaid break leaves 7.5 hours, which payroll usually wants as 7.50 decimal hours.
Why decimal hours are not 8.30
An hour has 60 minutes, not 100. Thirty minutes is half an hour, so 8 hours 30 minutes is 8.50. Writing 8.30 would short the total by 12 minutes when someone multiplies by an hourly rate.
Overnight and 12-hour shifts
Night shifts, hospital 7-to-7, and warehouse swing shifts all cross midnight or run long. This calculator treats an end time earlier than the start as the next calendar day. It does not decide what your employer counts as paid time. That is the timesheet and the contract.
FAQ
How many hours from 9 to 5 with a 30 minute lunch? Eight hours on the clock minus 30 minutes is 7 hours 30 minutes, or 7.50 decimal hours.
How do I calculate a 10pm to 6am shift? That is 8 hours before breaks. Subtract lunch the same way you would on a day shift.
Does this include overtime? No. Overtime rules depend on the job and the place. The weekly time card only flags hours over 40 in the week you typed, as arithmetic, not legal advice.