Working out hours between two times
Convert both times to minutes past midnight, subtract, then deduct any unpaid break. If the end time is earlier than the start, add 24 hours first — the shift crossed midnight.
If End < Start: add 24 hours to End first
Overnight shifts
A shift from 22:00 to 06:00 subtracts to −16 hours if handled naively. Adding 24 hours to the end time gives 30:00 − 22:00 = 8 hours, which is correct. This calculator detects the case automatically.
Decimal hours and the rounding trap
Payroll runs on decimal hours, because rates multiply cleanly. 8h 30m is 8.5 hours, not 8.30.
| Time | Decimal | Time | Decimal |
|---|---|---|---|
| 15 min | 0.25 | 6h 15m | 6.25 |
| 30 min | 0.50 | 7h 30m | 7.50 |
| 45 min | 0.75 | 8h 45m | 8.75 |
| 20 min | 0.33 | 7h 20m | 7.33 |
| 40 min | 0.67 | 8h 40m | 8.67 |
| 10 min | 0.17 | 9h 10m | 9.17 |
Legal rounding
US federal regulations permit rounding to the nearest quarter hour, provided the rounding is neutral over time — it must not systematically favour the employer. Rounding that only ever goes down is a violation. Some states, notably California, apply stricter interpretations.
Overtime and breaks
Under the US Fair Labor Standards Act, non-exempt employees earn 1.5× their regular rate for hours beyond 40 in a workweek. There is no federal daily overtime requirement — that comes from state law.
| Jurisdiction | Rule |
|---|---|
| US federal | 1.5× after 40 hours in a week |
| California | 1.5× after 8 hours a day, 2× after 12; 1.5× on the 7th consecutive day |
| Alaska, Nevada | 1.5× after 8 hours a day |
| Colorado | 1.5× after 12 hours a day or 40 a week |
| India (Factories Act) | 2× after 9 hours a day or 48 a week |
| UK | No statutory overtime premium; contractual only |
| EU Working Time Directive | 48-hour weekly average cap, not a pay premium |
Breaks
Whether a break is paid depends on length and jurisdiction. Under US federal rules, breaks under 20 minutes are generally compensable and count toward hours worked, while bona fide meal periods of 30 minutes or more are not — provided the employee is fully relieved of duty.
For a full week of shifts, use the time card calculator. For salary conversions, the salary calculator.
Frequently asked questions
How do I calculate hours worked?
Subtract the start time from the end time, then deduct unpaid breaks. From 09:00 to 17:30 is 8h 30m; less a 30-minute break, that is 8 hours.
If the end time is earlier than the start, the shift crossed midnight — add 24 hours to the end first.
How do I convert hours and minutes to decimal?
Divide the minutes by 60 and add to the hours. 8h 30m is 8 + 30÷60 = 8.5 hours.
Writing it as 8.30 is the classic error and underpays by 12 minutes.
Do unpaid breaks count as hours worked?
Generally not, if you are fully relieved of duty. Under US federal rules, bona fide meal periods of 30 minutes or more are unpaid, while short breaks under 20 minutes are compensable.
If you must remain at your desk or answer calls, it usually counts as work time regardless of what it is called.
When does overtime start?
Under US federal law, after 40 hours in a workweek at 1.5×. Some states add daily thresholds — California requires 1.5× after 8 hours in a day and 2× after 12.
Other countries differ substantially; the UK has no statutory overtime premium at all.
Can my employer round my hours?
In the US, yes, to the nearest quarter hour — but the rounding must be neutral over time. Rounding that consistently favours the employer is unlawful.
Some states apply stricter standards, and several court decisions have limited the practice further.