How to Convert Work Hours to Decimal for Payroll

You can’t multiply “8 hours 45 minutes” by an hourly rate directly, minutes aren’t base-100, they’re base-60. Here’s exactly how to convert time worked into decimal hours for accurate payroll, plus the legal rule most guides skip.

Why you can’t just use the minutes as-is

Treating 8 hours 45 minutes as “8.45” and multiplying by an hourly rate is a common, costly mistake. Minutes need to be converted to a fraction of an hour first, since there are 60 minutes in an hour, not 100.

The conversion formula

Decimal Hours = Whole Hours + (Minutes ÷ 60)

Minutes-to-decimal quick reference

Minutes	Decimal
15 min	0.25
20 min	0.33
30 min	0.50
40 min	0.67
45 min	0.75
50 min	0.83

Worked example

An employee clocks in at 9:08 AM and out at 5:28 PM, earning $22/hour:

Convert to 24-hour time: 9:08 to 17:28.
Subtract: 17:28 − 9:08 = 8 hours 20 minutes.
Convert minutes to decimal: 20 ÷ 60 = 0.33.
Decimal hours: 8.33.
Gross pay: 8.33 × $22 = $183.26.

Enter any two clock times directly into our time calculator to get the exact duration without doing this by hand.

The rounding rule most guides don’t mention

The US Department of Labor permits rounding to the nearest 5, 6, or 15-minute increment for payroll convenience. But there’s a catch: rounding must be applied neutrally over time, not consistently in the employer’s favor. Systematically rounding down against employees can constitute a wage and hour violation under the Fair Labor Standards Act (FLSA). If you round, apply the same rule to everyone, every time, in both directions.

Handling overtime

Under FLSA, non-exempt employees working over 40 hours in a workweek are generally entitled to overtime pay at 1.5 times their regular rate for the excess hours. Add up decimal hours for the full week first, then apply the overtime rate only to hours beyond 40.

Common payroll time mistakes

Treating minutes as if they’re decimal already (45 minutes ≠ 0.45 hours; it’s 0.75).
Mixing AM/PM without converting to 24-hour time, which can silently produce a negative or wildly wrong duration.
Rounding inconsistently between employees or pay periods, which creates both payroll errors and legal exposure.
Forgetting unpaid breaks should typically be subtracted from total time before converting to decimal hours.

How do I convert 45 minutes to decimal hours?

Divide 45 by 60, which equals 0.75. So 45 minutes is 0.75 of an hour.

Is it legal to round employee time for payroll?

Yes, the Department of Labor permits rounding to the nearest 5, 6, or 15-minute increment, but the rounding must be neutral over time and can’t systematically shortchange employees, or it risks violating the FLSA.

How do I calculate overtime pay from decimal hours?

Add up total decimal hours for the workweek. Any hours beyond 40 are typically paid at 1.5 times the regular hourly rate for non-exempt employees under FLSA rules.

What’s the easiest way to calculate hours worked from clock-in and clock-out times?

Convert both times to 24-hour format, subtract the start from the end time, and convert any remaining minutes to a decimal by dividing by 60, or use a time calculator to skip the manual math.