How to Calculate Work Hours in Four Steps
Every payroll department on earth runs the same core calculation, and it takes about ten seconds once you know it. Record your clock-in time, record your clock-out time, subtract to get your gross shift length, then subtract your unpaid breaks. That is the entire formula: net work hours = end time minus start time minus unpaid breaks.
The step people get wrong is the last one. Under the Fair Labor Standards Act, bona fide meal breaks of 30 minutes or more are typically unpaid and get deducted, while short rest breaks of 20 minutes or less are usually paid and stay in your total. That is why the calculator above lets you mark each break as paid or unpaid separately. Enter them honestly and the net hours match what should appear on your pay stub.
Gross Hours vs Net Hours: Why the Distinction Matters
Gross hours are the full span from clock-in to clock-out, breaks included. Net hours are what you actually get paid for. A retail shift from 11:00 AM to 7:45 PM is 8 hours 45 minutes gross, but with a 30-minute unpaid meal break the net is 8.25 hours. If your employer pays hourly, net hours are the number that multiplied by your rate, so it is worth double-checking that your timesheet deducts only what it should.
Want to see what those hours are worth? Once you have your net total, run it through our paycheck calculator to estimate your actual take-home pay after federal taxes, Social Security, and Medicare. And if you need to log a whole week of shifts instead of a single day, our time card calculator totals daily entries into a weekly timesheet.
Decimal Hours: The Format Payroll Actually Uses
Timesheets and payroll systems record hours in decimal format, not hours and minutes, and the conversion trips up a remarkable number of people. Decimal hours = whole hours + (minutes / 60). So 7 hours 45 minutes is 7.75 hours, not 7.45. Writing 8:20 as 8.20 instead of 8.33 shortchanges you 8 minutes of pay every time it happens.
| Clock time | Decimal hours |
| 7:15 | 7.25 |
| 7:30 | 7.50 |
| 7:45 | 7.75 |
| 8:20 | 8.33 |
| 8:40 | 8.67 |
The calculator shows both formats side by side, so you can copy the decimal figure straight into your timesheet. If your employer rounds to the nearest quarter hour or tenth of an hour, use the payroll rounding setting above to match their policy before you submit.
Overnight Shifts and the Weekly Timesheet
Night shifts break naive subtraction, because 6:00 AM minus 10:00 PM is a negative number. The fix is automatic: whenever the end time is earlier than the start time, the calculator treats the shift as crossing midnight and adds 24 hours to the end. A 10:00 PM to 6:30 AM shift with a 30-minute break computes as 8.5 minus 0.5 = 8.0 hours, no mental gymnastics required.
For weekly totals, switch to the timesheet tab and enter each day's start, end, and break minutes. The calculator sums the week and flags overtime using the standard US threshold of 40 hours per workweek at 1.5 times the regular rate. State rules can differ, California for example requires daily overtime after 8 hours, so treat the estimate as a starting point and check your state's labor rules.
Frequently Asked Questions
How do I calculate my work hours?
Subtract your clock-in time from your clock-out time to get gross hours, then subtract unpaid breaks. Clocking in at 9:00 AM and out at 5:00 PM with a 30-minute unpaid lunch gives 8.0 minus 0.5 = 7.5 net work hours. The calculator above does this instantly, including overnight shifts and multiple break periods.
How many hours is 9 to 5 with a 30 minute lunch?
A 9 AM to 5 PM shift is 8 gross hours. After subtracting a 30-minute unpaid lunch, net work hours are 7.5, or 7.50 decimal hours. With a full one-hour lunch instead, the net drops to 7.0 hours.
How do I convert work hours to decimal?
Divide the minutes by 60 and add the result to the whole hours. For example, 45 / 60 = 0.75, so 8 hours 45 minutes = 8.75 decimal hours. Common conversions: 15 minutes = 0.25, 30 minutes = 0.50, 45 minutes = 0.75.
How do you calculate an overnight shift?
When the end time is earlier than the start time, the shift crossed midnight, so add 24 hours to the end time before subtracting. A 10:00 PM to 6:00 AM shift is (6 + 24) - 22 = 8 gross hours, then subtract any unpaid breaks for the net total.
What is the difference between gross and net work hours?
Gross hours are the total time from clock-in to clock-out, including all breaks. Net hours are gross hours minus unpaid break time. Only unpaid breaks get deducted; paid rest breaks remain part of your total.
Last updated: 2026 | Overtime rules reference the federal Fair Labor Standards Act. Estimates are for planning only and do not determine legal entitlement.