Whether you are on a timesheet, billing clients or checking your paycheck, hours worked follows one simple rule — and a few traps.
The basic formula
Hours worked = (End time − Start time) − unpaid breaks
Times must be in 24-hour (military) format for the subtraction to work.
How to calculate hours worked step by step
- Convert both times to 24-hour format: 1:30 pm → 13:30.
- Subtract the start time from the end time.
- Convert minutes to a decimal: 45 min ÷ 60 = 0.75, so 7h 45m = 7.75 hours.
- Subtract unpaid breaks (lunch) from the total.
A worked example
Shift 9:00 am → 5:30 pm with a 45-minute unpaid lunch:
- End − start: 17:30 − 9:00 = 8 hours 30 minutes
- Decimal: 8.5 hours
- Minus lunch: 8.5 − 0.75 = 7.75 hours
At $20/hour: 7.75 × 20 = $155.00 gross pay.
The minutes-to-decimal table
- 15 min = 0.25
- 30 min = 0.50
- 45 min = 0.75
Payroll almost always uses decimals — 7h 30m is 7.5, not 7.30.
Overnight shifts
If the end time is smaller than the start, add 24 hours first: a 10:00 pm → 6:00 am shift is (6 + 24) − 22 = 8 hours.
Weekly totals
Add each day's decimal hours: 7.75 + 8 + 7.75 + 8 + 7.5 = 39 hours → one hour of overtime at time-and-a-half in the US after 40 in a week.
Put it into practice
For multi-day spans, use the free Date Difference Calculator to count days between punch dates, and check Age Calculator style date math for anniversaries and tenure.
