The correct minutes-to-decimal formula
Use decimal hours = whole hours + (minutes ÷ 60). For 8 hours 20 minutes, divide 20 by 60 to get 0.3333, then add 8 for 8.3333 hours.
Do not write 8 hours 30 minutes as 8.30. The digits after a decimal represent tenths and hundredths of an hour; 0.30 hour equals only 18 minutes.
Useful payroll conversion values
Exact conversions often repeat, so a displayed value may need rounding. Retain enough precision during calculation and round only the final value according to the payroll system’s documented policy.
- 5 minutes = 0.0833 hour
- 6 minutes = 0.1000 hour
- 10 minutes = 0.1667 hour
- 15 minutes = 0.2500 hour
- 20 minutes = 0.3333 hour
- 30 minutes = 0.5000 hour
- 45 minutes = 0.7500 hour
Conversion is not the same as time-clock rounding
Converting 9 hours 7 minutes to 9.1167 hours preserves the duration. Rounding a clock punch to a 5-, 6-, or 15-minute increment changes the recorded value. Keep these operations separate so the audit trail shows what was measured and what policy was applied.
The main time-card calculator calculates duration from clock times, subtracts entered unpaid breaks, and displays decimal totals automatically.