How to Calculate Work Hours Correctly

By Intious · Updated September 7, 2026

Quick answer

Subtract the clock-in time from the clock-out time, adjust overnight shifts by adding 24 hours when needed, and then subtract unpaid breaks. Add the daily results before applying weekly overtime rules.

Start with elapsed time

For a same-day shift, subtract the starting time from the ending time. A shift from 8:15 AM to 4:45 PM spans 8 hours 30 minutes. Keep the result as hours and minutes until the final step to avoid rounding errors.

Subtract only unpaid time

A paid break remains part of worked time. An unpaid lunch is deducted. If the 8-hour-30-minute shift includes a 30-minute unpaid lunch, the worked total is exactly 8 hours.

Handle overnight shifts

When the clock-out time is earlier than the clock-in time, the shift crosses midnight. Treat the ending time as belonging to the following day. From 10:00 PM to 6:30 AM is 8 hours 30 minutes before breaks.

Convert minutes to decimals

Payroll decimals are fractions of an hour. Divide minutes by 60: 15 minutes is 0.25, 30 is 0.50 and 45 is 0.75. Do not write 8:30 as 8.30 decimal hours; the correct value is 8.50.

Check the week before checking the paycheck

Take a five-day timecard with 8, 8, 9, 7.5 and 8 paid hours. The total is 40.5 hours. Under the calculator’s simple 40-hour threshold, 40 hours are regular and 0.5 is overtime. At $20 per hour, estimated gross is $800 + $15 = $815. If your own total differs, compare the daily durations first, then the break deductions, and only then the pay settings. A missing half-hour break and a wrong overtime threshold can produce similar-looking pay differences for completely different reasons.

Try it with your numbers

Add clock-in and clock-out times, subtract breaks, and see regular and overtime hours.

Work Hours Calculator

Official guidance

U.S. Department of Labor: hours worked · U.S. Department of Labor: regular rate of pay

Next steps

Calculation limitations · Report a correction

Frequently asked questions

How do I calculate hours worked with a lunch break?

Subtract clock-in from clock-out, then subtract the genuinely unpaid break. A 09:00–17:30 shift with 30 unpaid minutes is 8 worked hours. Do not deduct a break merely because it is called lunch; verify how it was actually taken and recorded.

Is 7 hours 30 minutes the same as 7.30 hours?

No. Thirty minutes is 30 ÷ 60 = 0.5 hour, so the decimal total is 7.5 hours. Conversely, 7.30 decimal hours is 7 hours 18 minutes.

Does the calculator handle overnight shifts?

Yes. An end time earlier than the start is treated as the following day. Equal start and end times mean zero, not a 24-hour shift. Date-specific daylight-saving changes are not modeled.

Why does the estimate differ from my payslip?

Check break deductions, rounding, workweek boundaries, multiple rates and premiums. The displayed gross estimate is before taxes and deductions and is not a payroll determination.

Why does my timecard show 8.50 instead of 8:30?

8.50 is decimal notation for eight and a half hours. 8:30 expresses the same duration as hours and minutes. Convert the units before comparing the two records.

Check the assumptions against the Work Hours Calculator and keep the inputs alongside your result. For a discrepancy, send an anonymous worked example rather than private employee records.

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