Decimal hours are how payroll systems store time. 7 hours 30 minutes becomes 7.5 hours. 8:15 becomes 8.25. The conversion is just minutes ÷ 60, but a full reference chart is helpful when you're reading a timesheet or filling out a contractor invoice. Here's every conversion plus why this matters.
Decimal hours = whole hours + (minutes ÷ 60)
Examples:
Just four numbers cover most timesheets:
| Minutes | Decimal | Memory trick |
|---|---|---|
| 15 min | 0.25 | Quarter past = quarter hour = 0.25 |
| 30 min | 0.50 | Half past = half hour = 0.50 |
| 45 min | 0.75 | Quarter to = three quarters = 0.75 |
| 60 min | 1.00 | One full hour |
| Minutes | Decimal hours | Minutes | Decimal hours |
|---|---|---|---|
| 1 | 0.017 | 31 | 0.517 |
| 2 | 0.033 | 32 | 0.533 |
| 3 | 0.050 | 33 | 0.550 |
| 4 | 0.067 | 34 | 0.567 |
| 5 | 0.083 | 35 | 0.583 |
| 6 | 0.100 | 36 | 0.600 |
| 7 | 0.117 | 37 | 0.617 |
| 8 | 0.133 | 38 | 0.633 |
| 9 | 0.150 | 39 | 0.650 |
| 10 | 0.167 | 40 | 0.667 |
| 11 | 0.183 | 41 | 0.683 |
| 12 | 0.200 | 42 | 0.700 |
| 13 | 0.217 | 43 | 0.717 |
| 14 | 0.233 | 44 | 0.733 |
| 15 | 0.250 | 45 | 0.750 |
| 16 | 0.267 | 46 | 0.767 |
| 17 | 0.283 | 47 | 0.783 |
| 18 | 0.300 | 48 | 0.800 |
| 19 | 0.317 | 49 | 0.817 |
| 20 | 0.333 | 50 | 0.833 |
| 21 | 0.350 | 51 | 0.850 |
| 22 | 0.367 | 52 | 0.867 |
| 23 | 0.383 | 53 | 0.883 |
| 24 | 0.400 | 54 | 0.900 |
| 25 | 0.417 | 55 | 0.917 |
| 26 | 0.433 | 56 | 0.933 |
| 27 | 0.450 | 57 | 0.950 |
| 28 | 0.467 | 58 | 0.967 |
| 29 | 0.483 | 59 | 0.983 |
| 30 | 0.500 | 60 | 1.000 |
Some employers and government contracts use tenth-hour rounding, where time is recorded in increments of 6 minutes (0.1 hour). The conversions:
| Time worked | Tenth-hour decimal |
|---|---|
| 0–3 minutes | 0.0 (rounded down) |
| 3–9 minutes | 0.1 |
| 9–15 minutes | 0.2 |
| 15–21 minutes | 0.3 |
| 21–27 minutes | 0.4 |
| 27–33 minutes | 0.5 |
| 33–39 minutes | 0.6 |
| 39–45 minutes | 0.7 |
| 45–51 minutes | 0.8 |
| 51–57 minutes | 0.9 |
| 57–60 minutes | 1.0 |
Multiplication. With decimal time, hourly pay is a simple multiplication:
With HH:MM time, you'd need to convert to minutes first (480 minutes × $0.33/min) or write out the math more carefully. Every payroll system stores time in decimal under the hood, even if it displays HH:MM.
Formula: hours = whole number of hours, minutes = decimal × 60
0.30 hours is 18 minutes (0.30 × 60), not 30 minutes. 30 minutes is 0.50 hours. This is the most common mistake on hand-calculated timesheets.
If you have 7 hours 20 minutes and round to 7.3 hours, you've actually lost 2 minutes. 7 hours 20 min is precisely 7.333... hours. For payroll over a year, those rounding losses add up.
European countries write decimals with a comma (7,5 hours). US/UK use a period (7.5 hours). Same number, different notation — but spreadsheet imports get confused.
The Hours Calculator has a built-in Decimal tab — type in either HH:MM or decimal form and see the conversion both ways. The Time Adder accepts decimal entries too.
Published May 2026. Spot an error? Email contactus@calculatehours.net.