How to calculate hours between two times
Clock time runs in base 60 and payroll runs in base 10, which is why “8 hours 30 minutes” becomes 8.50 and not 8.30. The safest order of operations is always the same: whole span first, break second, conversion last.
- 11. Take the whole spanEnd time minus start time. If the end is earlier than the start, the shift crossed midnight — add 24 hours.
- 22. Subtract the unpaid breakOnly bona fide meal periods come off. Short rest breaks of 5 to 20 minutes stay in.
- 33. Convert to decimalDivide the leftover minutes by 60: 15 min = 0.25, 30 min = 0.50, 45 min = 0.75.
- 44. Check against the paystubCompare the decimal hours with the hours printed on your pay statement, not the hh:mm figure.
Common shifts at a glance
Every row below assumes the break shown is unpaid. These are the shift patterns people look up most often:
| Shift | On the clock | Break | Paid hours | Decimal |
|---|---|---|---|---|
| 9:00 AM – 5:00 PM | 8:00 | 30 min | 7:30 | 7.50 |
| 9:00 AM – 5:00 PM | 8:00 | 60 min | 7:00 | 7.00 |
| 8:00 AM – 4:30 PM | 8:30 | 30 min | 8:00 | 8.00 |
| 7:00 AM – 3:30 PM | 8:30 | 30 min | 8:00 | 8.00 |
| 6:00 AM – 2:00 PM | 8:00 | 0 min | 8:00 | 8.00 |
| 8:00 AM – 6:00 PM | 10:00 | 60 min | 9:00 | 9.00 |
| 7:00 AM – 7:00 PM | 12:00 | 60 min | 11:00 | 11.00 |
| 10:00 PM – 6:00 AM | 8:00 | 30 min | 7:30 | 7.50 |
| 11:00 PM – 7:30 AM | 8:30 | 30 min | 8:00 | 8.00 |
Minutes to decimal hours
The conversion table below is the one worth memorizing — it covers almost every partial hour that shows up on a timesheet.
| Minutes | Decimal | Minutes | Decimal |
|---|---|---|---|
| 5 min | 0.08 | 35 min | 0.58 |
| 10 min | 0.17 | 40 min | 0.67 |
| 15 min | 0.25 | 45 min | 0.75 |
| 20 min | 0.33 | 50 min | 0.83 |
| 25 min | 0.42 | 55 min | 0.92 |
| 30 min | 0.50 | 60 min | 1.00 |
Sources
- 29 CFR 785.19 — Meal periods“Bona fide meal periods are not worktime… The employee must be completely relieved from duty for the purposes of eating regular meals. Ordinarily 30 minutes or more is long enough for a bona fide meal period.”
- 29 CFR 785.18 — Rest periods“Rest periods of short duration, running from 5 minutes to about 20 minutes… must be counted as hours worked.”
- U.S. Department of Labor — Hours WorkedWage and Hour Division overview of the Fair Labor Standards Act, including which time is counted as hours worked.
Frequently asked questions
How many hours is 9 to 5?
How many hours is 7 AM to 3:30 PM?
How do I calculate hours worked with a lunch break?
How do I convert 8 hours and 45 minutes to decimal?
Is my unpaid lunch break really unpaid?
Under 29 CFR 785.19, “bona fide meal periods are not worktime.” The employee “must be completely relieved from duty for the purposes of eating regular meals” and “ordinarily 30 minutes or more is long enough.” If you have to keep working while eating, the break is not bona fide and counts as hours worked.
Should short coffee breaks be deducted?
No. 29 CFR 785.18 states that rest periods “running from 5 minutes to about 20 minutes … must be counted as hours worked.” Only longer bona fide meal periods get deducted.