Convert hours, minutes, and seconds to decimal hours, or convert decimal hours back to hours, minutes, and seconds with this calculator.
- 100 Minute Clock Calculator
- Tenth of an Hour Calculator
- Hours to Decimal Calculator
- Decimals to Time Calculator
- Subtract Time Calculator
- All Unit Converters
Fraction of an Hour Formula
The calculator runs one of two formulas depending on which tab you pick.
Time to decimal hours:
Decimal hours = H + M/60 + S/3600
Decimal hours to time:
Total seconds = D * 3600
Variables:
- H = whole hours
- M = minutes (0 to 59)
- S = seconds (0 to 59)
- D = decimal hours
The “Time to decimal” mode adds your hours, minutes, and seconds together after converting each to hours, then reports the result as a decimal and as a reduced fraction of an hour. The “Decimal to time” mode multiplies your decimal value by 3600 to get total seconds, then splits that into hours, minutes, and seconds.
Common Fractions of an Hour
Use this table to convert minutes to a fraction or decimal hour at a glance.
| Minutes | Fraction of hour | Decimal hour |
|---|---|---|
| 5 | 1/12 | 0.0833 |
| 6 | 1/10 | 0.10 |
| 10 | 1/6 | 0.1667 |
| 12 | 1/5 | 0.20 |
| 15 | 1/4 | 0.25 |
| 20 | 1/3 | 0.3333 |
| 30 | 1/2 | 0.50 |
| 40 | 2/3 | 0.6667 |
| 45 | 3/4 | 0.75 |
| 50 | 5/6 | 0.8333 |
Payroll systems usually round to two decimal places. The table below shows how a partial hour gets recorded on a timesheet.
| Time worked | Payroll decimal |
|---|---|
| 7 hr 30 min | 7.50 |
| 8 hr 15 min | 8.25 |
| 8 hr 45 min | 8.75 |
| 9 hr 20 min | 9.33 |
| 10 hr 6 min | 10.10 |
Example Problems
Example 1. You worked 6 hours and 45 minutes. What fraction of an hour is the leftover, and what is the decimal total?
Decimal hours = 6 + 45/60 = 6 + 0.75 = 6.75 hours. The 45 minutes is 45/60, which reduces to 3/4 of an hour.
Example 2. A log file shows 2.4 hours. Convert that back to hours, minutes, and seconds.
Total seconds = 2.4 × 3600 = 8,640 seconds. That splits into 2 hours, 24 minutes, 0 seconds. The fraction after the whole hours is 24/60, or 2/5 of an hour.
FAQ
How do you turn minutes into a fraction of an hour?
Put the minutes over 60 and reduce. For 20 minutes, that is 20/60 = 1/3.
How do you turn minutes into a decimal hour?
Divide minutes by 60. For 20 minutes, that is 20 ÷ 60 = 0.3333 hours.
Why does my payroll decimal not match the exact value?
Payroll usually rounds to the nearest 0.01 hour, which is 36 seconds. A value like 9 hr 20 min is exactly 9.3333, but it shows as 9.33 on a timesheet.
What does the “fraction after whole hours” line mean?
It is the leftover time expressed as a reduced fraction of one hour. For 1 hour 30 minutes, the whole hour is 1 and the leftover is 30/60 = 1/2.
