Divide by 60
Payroll, timesheets and billing run on decimal hours, where 5.75 means five hours and forty-five minutes. To convert, just divide minutes by 60. The catch is that the decimal is not the minute count: 15 minutes is 0.25 hours, because a quarter of an hour is 0.25, not 0.15.
Minutes to decimal hours
| Minutes | Decimal hours | As HH:MM |
|---|---|---|
| 5 min | 0.083 | 0:05 |
| 10 min | 0.167 | 0:10 |
| 15 min | 0.25 | 0:15 |
| 20 min | 0.333 | 0:20 |
| 30 min | 0.5 | 0:30 |
| 45 min | 0.75 | 0:45 |
| 60 min | 1.0 | 1:00 |
| 90 min | 1.5 | 1:30 |
| 480 min | 8.0 | 8:00 |
The three that trip people up: 15 min = 0.25, 20 min = 0.33, 40 min = 0.67. When in doubt, minutes ÷ 60.
Getting it right on a timesheet
- 0.5 means half an hour, not half a minute. In payroll a bare decimal is always hours, so 0.5 is 30 minutes.
- Convert once, at the end. Log raw minutes as you work and convert the total, rather than converting each entry and rounding — separate roundings drift off the true figure.
- Then multiply by the rate. Decimal hours slot straight into pay: 4.083 hours at $75 is 4.083 × 75 = $306.25. HH:MM cannot be multiplied that way.
Common questions
How do I convert minutes to decimal hours?
Divide the minutes by 60. So 15 minutes is 0.25 hours, 45 minutes is 0.75, and 90 minutes is 1.5. This is the format payroll and billing software expect, not hours-and-minutes.
Why is 15 minutes 0.25 hours and not 0.15?
Because an hour has 60 minutes, not 100. Fifteen minutes is a quarter of an hour, and a quarter written as a decimal is 0.25. Writing 0.15 would be treating the hour as if it had 100 minutes, which underpays by ten minutes.
What is 8 hours 27 minutes in decimal?
Keep the 8, then divide the 27 minutes by 60: 27 / 60 = 0.45. So 8 hours 27 minutes is 8.45 decimal hours.
