Overnight Shift Calculator

How overnight hours are counted

The arithmetic is one line: when the end time is earlier on the clock than the start, add 24 hours to the end before subtracting. 6:30 AM is 390 minutes after midnight; as a next-day time it is 390 + 1,440 = 1,830. From a 10:00 PM start (1,320 minutes) that leaves 510 minutes — 8 hours 30 minutes. Unpaid breaks come off that figure in the usual way, using the break field above.

Common night shifts, already counted

Each of these is gross, before any break. A 12-hour hospital shift with an unpaid 30-minute meal break is 11.50 payable hours, not 12.00 — set the break field to 30 to see it.

Which day do the hours belong to?

Convention credits an overnight shift to the day it starts — a Friday 10 PM start is Friday's shift even though most of it happens on Saturday. That matters at the edge of a workweek, where moving a night shift across the boundary can move hours in or out of a 40-hour count. Employers do not all follow the same convention, and timesheet software differs too, so check how yours records it before relying on a week total. The time card calculator credits overnight days to the start day and says so under the card.

Night differentials are not in this number

Many employers pay a shift differential — an extra amount per hour for night work — and some jurisdictions nudge schedules with rest-period rules. That is a rate question, not a duration question: this page counts hours honestly, and the premium, if any, is applied by payroll on top. Rules vary widely; your contract and local labour standards are the source, not this calculator.

Frequently asked questions

How many hours is 7 PM to 7 AM?

12 hours exactly — 12.00 decimal, before breaks. It is the classic 12-hour night rotation in hospitals, security and manufacturing.

Why do other calculators give me a negative answer?

They subtract clock numbers directly: 6:30 minus 22:00 is negative because the end is "earlier". The fix is the next-day reading described above; the main duration calculator has it as a switch you can turn off, this page keeps it on.

Does the break come off before or after the midnight adjustment?

It makes no difference to the result — the break is subtracted from the total span, and the span is the same either way. 510 minutes gross minus a 30-minute break is 480 net, midnight or not.