Hours Calculator
Calculate hours worked between a start and end time, including overnight shifts and an unpaid break, as hours and minutes or decimal hours.
Written by Rahman · Last reviewed
Quick answer
Hours worked equals the time span between a start and end time, minus any unpaid break. From 09:00 to 17:30 is an 8.5-hour span; subtract a 30-minute break and the result is exactly 8 hours, or 8.00 decimal hours, the figure most timesheet and payroll systems expect.
Results are estimates for general guidance only. Double-check any figure you rely on for an important decision.
About the Hours Calculator
This calculator finds the elapsed time between a start and end clock time, subtracts an unpaid break, and reports the result both as hours and minutes and as decimal hours, the format most timesheets and payroll systems use for fractional time.
An end time earlier than the start time is treated as an overnight shift ending the next day, rather than an error, since that is a normal pattern for night-shift and hospitality work.
What counts as an unpaid break, and what rounding is allowed
The arithmetic of a shift is simple; what goes into it is where timesheets go wrong. Under US federal wage rules, not every break may be deducted and not every rounding practice is acceptable. State law and employment contracts can be more generous, and other countries have their own rules.
- Short rest breaks, from 5 to about 20 minutes, count as hours worked. They are not entered as an unpaid break.
- A meal period is unpaid only if the worker is completely relieved of duty, and 30 minutes or more is ordinarily long enough. Eating at a desk while still answering the phone is working time.
- Employers may round clock times to the nearest 5 minutes, tenth of an hour or quarter hour, provided the practice does not leave workers short over time. On quarter-hour rounding, a start of 8:07 is recorded as 8:00 and 8:08 as 8:15.
- Rounding that only ever runs in the employer's favour (late arrivals rounded up, early arrivals ignored) is what the rule excludes.
Decimal hours cause a separate, purely clerical error: 8 hours 20 minutes is 8.33 hours, not 8.20. Entering 8.20 on a timesheet records 8 hours 12 minutes, and across a five-day week that is 40 minutes of work that goes missing.
Frequently Asked Questions
How do I convert minutes to decimal hours?
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Divide the minutes by 60. 30 minutes is 0.5 hours, 45 minutes is 0.75 hours, and so on. This calculator does the conversion automatically.
Does this handle an overnight shift?
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Yes. If the end time is earlier than the start time, it is treated as ending the following day rather than being rejected.
Can I calculate a full week of shifts at once?
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This calculator handles one shift at a time. For a weekly total, add each shift's decimal-hours result together.
Sources
- 29 CFR Part 785 — Hours Worked (eCFR) — The US Department of Labor regulation behind the breaks and rounding section. §785.18 says rest periods of 5 to about 20 minutes "must be counted as hours worked"; §785.19 says a bona fide meal period requires the employee to be "completely relieved from duty" and that 30 minutes or more is ordinarily long enough; §785.48(b) accepts rounding to the nearest 5 minutes, one-tenth or quarter of an hour provided it does not, over time, fail to pay employees for all the time actually worked. US federal rules only.