Decimal Hours vs. Hours and Minutes: Converting Between Them
Why payroll uses decimal hours instead of hours and minutes, and a quick conversion table for the most common minute values.
A timesheet naturally reads in hours and minutes ("7 hours 30 minutes"), but payroll systems calculate pay in decimal hours ("7.5") — because decimal hours multiply cleanly against an hourly rate, while minutes don't (there are 60 minutes in an hour, not 100).
| Minutes | Decimal hours |
|---|---|
| 15 min | 0.25 |
| 30 min | 0.50 |
| 45 min | 0.75 |
| 10 min | 0.17 |
| 20 min | 0.33 |
| 40 min | 0.67 |
Why the mistake is common
It's tempting to read "7 hours 30 minutes" as "7.30" on a calculator — but that's wrong, because 30 minutes is half an hour, not three-tenths of one. The correct conversion divides minutes by 60: 30 ÷ 60 = 0.5, giving 7.5, not 7.3. That 0.2-hour gap compounds across every shift in a pay period.
The Time Card / Hours Calculator shows both formats side by side for every result, so there's never a need to convert by hand.