Minutes to Decimal Hours: Hundredths and Tenths
Every minute of the hour as a decimal hour, in the hundredths many payroll forms use and in the tenths some employers use, side by side.
To turn minutes into decimal hours, divide them by sixty: 45 minutes is 0.75 hours, so 8 hours 45 minutes is 8.75. Most minutes give a long decimal (20 minutes is 0.3333…), so payroll offices print the result rounded in a chart, like the one published on uhcl.edu. There are two kinds of chart, and they give different numbers.
- Hundredths of an hour, two decimal places. The chart published on uhcl.edu, the chart published on norcocollege.edu and the San José State University, Payroll System Decimal Conversion Chart print the same rows: minutes ÷ 60, rounded half up to two places. This is what CardHours shows.
- Tenths of an hour, one decimal place, in steps of 6 minutes. The University of Illinois System, Conversion Chart for Minutes to Tenths of Hours prints ranges: 1–2 minutes is .0, 3–8 minutes .1, and so on up to 57–60 minutes, 1.0.
Which one your card needs is your employer's choice; the form usually says how many decimal places to enter. In the chart below, 50 of the 60 minute rows come out differently in tenths than in hundredths; those rows are marked.
Minutes to decimal hours chart
| Minutes | Hundredths | Tenths | Tenths differ |
|---|---|---|---|
| 0 | 0.00 | 0.0 | |
| 1 | 0.02 | 0.0 | differs |
| 2 | 0.03 | 0.0 | differs |
| 3 | 0.05 | 0.1 | differs |
| 4 | 0.07 | 0.1 | differs |
| 5 | 0.08 | 0.1 | differs |
| 6 | 0.10 | 0.1 | |
| 7 | 0.12 | 0.1 | differs |
| 8 | 0.13 | 0.1 | differs |
| 9 | 0.15 | 0.2 | differs |
| 10 | 0.17 | 0.2 | differs |
| 11 | 0.18 | 0.2 | differs |
| 12 | 0.20 | 0.2 | |
| 13 | 0.22 | 0.2 | differs |
| 14 | 0.23 | 0.2 | differs |
| 15 | 0.25 | 0.3 | differs |
| 16 | 0.27 | 0.3 | differs |
| 17 | 0.28 | 0.3 | differs |
| 18 | 0.30 | 0.3 | |
| 19 | 0.32 | 0.3 | differs |
| 20 | 0.33 | 0.3 | differs |
| 21 | 0.35 | 0.4 | differs |
| 22 | 0.37 | 0.4 | differs |
| 23 | 0.38 | 0.4 | differs |
| 24 | 0.40 | 0.4 | |
| 25 | 0.42 | 0.4 | differs |
| 26 | 0.43 | 0.4 | differs |
| 27 | 0.45 | 0.5 | differs |
| 28 | 0.47 | 0.5 | differs |
| 29 | 0.48 | 0.5 | differs |
| 30 | 0.50 | 0.5 | |
| 31 | 0.52 | 0.5 | differs |
| 32 | 0.53 | 0.5 | differs |
| 33 | 0.55 | 0.6 | differs |
| 34 | 0.57 | 0.6 | differs |
| 35 | 0.58 | 0.6 | differs |
| 36 | 0.60 | 0.6 | |
| 37 | 0.62 | 0.6 | differs |
| 38 | 0.63 | 0.6 | differs |
| 39 | 0.65 | 0.7 | differs |
| 40 | 0.67 | 0.7 | differs |
| 41 | 0.68 | 0.7 | differs |
| 42 | 0.70 | 0.7 | |
| 43 | 0.72 | 0.7 | differs |
| 44 | 0.73 | 0.7 | differs |
| 45 | 0.75 | 0.8 | differs |
| 46 | 0.77 | 0.8 | differs |
| 47 | 0.78 | 0.8 | differs |
| 48 | 0.80 | 0.8 | |
| 49 | 0.82 | 0.8 | differs |
| 50 | 0.83 | 0.8 | differs |
| 51 | 0.85 | 0.9 | differs |
| 52 | 0.87 | 0.9 | differs |
| 53 | 0.88 | 0.9 | differs |
| 54 | 0.90 | 0.9 | |
| 55 | 0.92 | 0.9 | differs |
| 56 | 0.93 | 0.9 | differs |
| 57 | 0.95 | 1.0 | differs |
| 58 | 0.97 | 1.0 | differs |
| 59 | 0.98 | 1.0 | differs |
Why adding rounded days can miss the weekly total
A decimal shown for each day is already rounded, so adding the days adds their rounding too. Take three days of 8:00 AM to 3:50 PM with a 30-minute break, 7:20 each. Each day is 7.33 decimal hours, and three of those add up to 21.99. The minutes say otherwise: 3 × 440 = 1,320 minutes, exactly 22.00 hours.
| Day | In | Out | Break (min) | Hours | Decimal |
|---|---|---|---|---|---|
| Mon | 8:00 AM | 3:50 PM | 30 | 7:20 | 7.33 |
| Tue | 8:00 AM | 3:50 PM | 30 | 7:20 | 7.33 |
| Wed | 8:00 AM | 3:50 PM | 30 | 7:20 | 7.33 |
| Total | 22:00 | 22.00 | |||
CardHours adds the minutes first and converts the total once, so the week shows 22.00, and under
the total it says so when the rounded days would add up to something else: Daily decimals are rounded; the total uses exact
minutes.
At an hourly rate the difference reaches the pay as well; the calculator multiplies the minutes, not the rounded hours.
Converting by hand
- Split the time into hours and minutes: 7 hours 20 minutes.
- Divide the minutes by sixty: 20 ÷ 60 = 0.3333…
- Round to the places your form asks for: 0.33 in hundredths, or 0.3 in tenths.
- Put the hours back in front: 7.33.
For a week, add up all the minutes first, then convert once. The time card calculator does both for every row.