What are decimal hours?
Decimal hours express a duration as a single number rather than a pair of hours and minutes. Instead of writing 7 hours and 30 minutes, you write 7.5. The whole part counts the hours, and the digits after the decimal point represent the fraction of an hour. Half an hour is 0.5, a quarter hour is 0.25, and so on.
Most payroll systems, timesheet apps and accounting tools store worked time as decimal hours because it makes arithmetic and hourly rate calculations straightforward.
How to convert decimal hours to hours and minutes
The whole number is your hours. Multiply the decimal portion by 60 to get the minutes. A few worked examples:
- 7.5 hours = 7 hours 30 minutes (0.5 × 60 = 30)
- 1.25 hours = 1 hour 15 minutes (0.25 × 60 = 15)
- 8.75 hours = 8 hours 45 minutes (0.75 × 60 = 45)
- 6.10 hours = 6 hours 6 minutes (0.10 × 60 = 6)
How to convert hours and minutes to decimal
Divide the minutes by 60, then add the result to the hours. The formula is:decimal = hours + (minutes / 60).
- 7 hours 15 minutes = 7.25 hours
- 7 hours 30 minutes = 7.5 hours
- 7 hours 45 minutes = 7.75 hours
- 8 hours 45 minutes = 8.75 hours
Quick reference: minutes to decimal hours
Use this table to look up the decimal value of any number of minutes between 1 and 60. Values are rounded to four decimals, which is enough for any payroll or invoicing system.
Common decimal hour values
The decimal values most often seen on timesheets and invoices, with their exact hours and minutes equivalent.
| Decimal hours | Hours and minutes |
|---|---|
| 0.1 | 6 minutes |
| 0.25 | 15 minutes (quarter hour) |
| 0.33 | 20 minutes (one third) |
| 0.5 | 30 minutes (half hour) |
| 0.66 | 40 minutes (two thirds) |
| 0.75 | 45 minutes (three quarters) |
| 1.25 | 1 hour 15 minutes |
| 1.5 | 1 hour 30 minutes |
| 1.75 | 1 hour 45 minutes |
| 2.5 | 2 hours 30 minutes |
| 7.5 | 7 hours 30 minutes |
| 8.25 | 8 hours 15 minutes |
Rounding rules used in payroll
Most timesheet systems round worked time before turning it into decimal hours. The three rules below cover almost every payroll and billing context.
The 7 minute rule (nearest 15 minutes)
Standard rule under the US Fair Labor Standards Act. Time is rounded to the nearest quarter hour. From 1 to 7 minutes round down, from 8 to 14 minutes round up. The result is always a clean 0.00, 0.25, 0.50 or 0.75 decimal value.
Tenths of an hour (nearest 6 minutes)
Common in legal, accounting and consulting billing. Each tenth of an hour is 6 minutes, so worked time is recorded as 0.1, 0.2, 0.3 and so on. It keeps invoices easy to read and matches the way most legal billing software stores time.
Nearest minute
Used by modern digital timesheets and time tracking apps where clock-in and clock-out events are precise. The decimal output usually carries 2 or 3 decimals to stay accurate.
Decimal hours vs time of day
A common confusion: 7.5 decimal hours is not the same as 7:30 on a clock. Decimal hours measure a duration (how long something lasted), while a time like 7:30 AM points to a specific moment in the day. The decimal value 7.5 simply means 7 hours and 30 minutes of elapsed time, which is why it is the natural format for payroll, invoicing and project tracking.
Common use cases
- Filling in payroll timesheets that require decimal hour entries.
- Invoicing clients on an hourly basis as a freelancer or contractor.
- Tracking project time across multiple sessions and summing the totals.
- Reconciling clock-in / clock-out records with your finance team.
- Estimating costs by multiplying decimal hours by an hourly rate.