How to Calculate Hours Worked
Turn clock-in and clock-out times into hours and decimal hours for payroll — including breaks and overnight shifts — without the arithmetic headaches.
Adding up hours from a timesheet sounds easy until you hit a 30-minute lunch, a shift that crosses midnight, or the need to convert “8 hours 20 minutes” into a number payroll can multiply. This guide clears all three up.
Hours Calculator
The hours and minutes between two times.
Example
This is a sample result, not your calculation. Enter your own values to replace it.
Enter a start time and an end time, then calculate the hours between them.
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For payroll
- Decimal hours
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Check your entries
Enter a valid start and end time, and a break of zero or more minutes, to calculate.
Hours Between Two Dates
Give each time a date, and the span can run over several days.
Example
This is a sample result, not your calculation. Enter your own values to replace it.
Enter a start date and time and an end date and time to see the span between them.
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In other units
- Days, hours, minutes
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- Decimal hours
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Check your entries
Enter a valid date and time for both the start and the end.
The basic calculation
Hours worked is simply end time minus start time, minus any unpaid break. The catch is that time is in base 60, not base 10 — so 5:45 PM − 9:00 AM isn’t “8.45 hours.” Convert to minutes, subtract, then convert back. The calculator above does this for you.
Decimal hours for payroll
Payroll systems multiply hours by an hourly rate, so they need decimal hours, not hours-and-minutes. The conversion is minutes ÷ 60:
- 15 minutes = 0.25 hours
- 30 minutes = 0.5 hours
- 45 minutes = 0.75 hours
- 20 minutes = 0.33 hours
So 8 hours 30 minutes is 8.5 decimal hours. At $20/hour, that’s 8.5 × 20 = $170.
Overnight shifts
If a shift starts at 10:00 PM and ends at 6:00 AM, a naive subtraction gives a negative number. The fix is to recognise the clock crossed midnight and add 24 hours — giving the correct 8 hours. The calculator handles this automatically when the end time is earlier than the start.
Don’t forget breaks
Unpaid breaks come straight off the total. A 9-to-5 with a 30-minute lunch is 7.5 paid hours, not 8. Enter the break in minutes and it’s deducted for you.
A note on rounding
Employers often round to the nearest quarter-hour, and rules vary by jurisdiction. Use the hours calculator for the exact figure, then apply your workplace’s official rounding policy.