The steps
- Write each time as hours and minutes. Convert to 24-hour time if it helps (5:30 PM = 17:30).
- Subtract the in time from the out time. If the answer is negative, add 24 hours: the shift went past midnight.
- Subtract unpaid breaks (paid breaks stay in).
- Add the days. For payroll, convert to decimal by dividing the minutes by 60.
Minutes = out − in (add 24 h if out is earlier than in)
Net minutes = minutes − unpaid break
Decimal hours = net minutes ÷ 60
Worked examples
| Shift | In | Out | Break | Hours | Decimal |
|---|---|---|---|---|---|
| Standard day | 9:00 AM | 5:30 PM | 30 min | 8:00 | 8.00 |
| Early start | 8:15 AM | 4:45 PM | 0 | 8:30 | 8.50 |
| Overnight shift | 10:00 PM | 6:00 AM | 30 min | 7:30 | 7.50 |
| Short day | 7:50 AM | 12:10 PM | 0 | 4:20 | 4.33 |
Split shifts
For a split shift, work out each in/out pair and add them. 7:00 AM to 11:30 AM plus 1:00 PM to 4:30 PM is 4:30 + 3:30 = 8:00. The time card calculator has a split-shift option that adds both pairs for you.
Common mistakes
- AM/PM mix-ups: 9 to 5 is 8 hours, not 20. Type 9a and 5p to be sure.
- Subtracting minutes like decimals: 8:15 minus 7:45 is 0:30, not 0.70.
- Forgetting the break: unpaid lunch comes out of the total.
Not legal, tax or payroll advice. Rules depend on your state, job and whether you are exempt. Check with your employer or your state labor department.