Quick answer: Hours worked = clock out − clock in − unpaid break. 9:00 to 17:30 with a 30-minute lunch is 8 hours. Add the days together, and any hours over 40 in the week are overtime at 1.5× under the FLSA.
How to calculate hours worked
hours worked = (clock out − clock in) − unpaid breakUse 24-hour times. Deduct unpaid breaks, leave paid breaks in.The reliable way by hand is to turn each time into minutes since midnight, subtract, then divide by 60. That avoids the base-60 slips that come from subtracting 5:30 PM from 9:00 AM directly.
A standard day: 9:00 to 17:30 with a 30-minute lunch
- Time on the clock: 17:30 − 9:00 = 8 h 30 min
- Minus the unpaid break: 8 h 30 min − 30 min = 8 h 0 min
- In decimal: 8.00 hours
Result: 8.00 hours
Overnight shifts and the midnight rollover
A shift from 22:00 to 06:00 gives −16 hours if you subtract straight. When clock-out is earlier than clock-in, add 24 hours to the clock-out first: 30:00 − 22:00 = 8 hours. The calculator does this automatically.
How overtime works
Under the US Fair Labor Standards Act, non-exempt employees earn 1.5 times their regular rate for every hour over 40 in a workweek. Breaks come out first, then the 40-hour line is applied to what remains.
A week with overtime: 46 hours at $20 per hour
- Regular: 40 h × $20 = $800
- Overtime: 6 h × $30 (1.5 × $20) = $180
- Gross pay: $800 + $180 = $980
Result: $980 gross
- Federal overtime is weekly. Four 11-hour days (44 h) give 4 hours of overtime, the same as 44 hours spread over more days.
- Some states add daily overtime. California requires overtime after 8 hours in a day and double time after 12. This calculator uses a weekly threshold, so check daily rules separately.
Paid vs unpaid breaks
- Meal breaks, usually unpaid. A real meal period of 30 minutes or more, free of duties, is deducted.
- Short rest breaks, usually paid. Breaks of about 5 to 20 minutes count as working time and are not deducted.
So a 15-minute coffee break stays in, and a 45-minute lunch comes out. Only enter unpaid minutes in the break column.
Payroll rounding
Some employers round each entry, most often to the quarter hour, where 1 to 7 minutes round down and 8 or more round up. Under the FLSA this is only allowed if it is neutral over time. Since time clocks record exact minutes, paying actual time is the simplest and safest choice, which is why the calculator defaults to exact.
Most common error: A shift ending at 5:15 is 5.25, not 5.15, because 15 minutes is a quarter of an hour. Divide minutes by 60 before multiplying by a rate. The hours to decimal calculator shows the working.
Common mistakes when totalling hours
- Reading clock minutes as decimals. 8:45 is 8.75 hours, not 8.45.
- Forgetting the overnight rollover. Add 24 hours to the out-time before subtracting.
- Applying overtime to on-clock time. Deduct unpaid breaks first.
- Deducting paid rest breaks. Short breaks are usually paid time.
- Rounding every day then summing. Rounding the weekly total once distorts less.
Frequently asked questions
How do I calculate hours worked?
Subtract the clock-in time from the clock-out time, then subtract any unpaid break. 9:00 to 17:30 with a 30-minute lunch is 8.5 − 0.5 = 8 hours. Total each day and add them for the week.
How is overtime calculated?
Under the FLSA, non-exempt employees earn 1.5 times their regular rate for hours over 40 in a workweek. 46 hours at $20 is 40 × $20 = $800 plus 6 × $30 = $180, so $980 gross.
How do I calculate hours for an overnight shift?
Add 24 hours to the clock-out time before subtracting. 22:00 to 06:00 becomes 30:00 − 22:00 = 8 hours. The calculator does this when clock-out is earlier than clock-in.
Should breaks be deducted from hours worked?
Unpaid meal breaks of 30 minutes or more are deducted. Short rest breaks of about 5 to 20 minutes are usually paid working time and stay in.
What rounding is allowed on a timesheet?
Employers may round to the nearest 15, 10, 6 or 5 minutes only if rounding is neutral over time. Several states are stricter, and paying exact recorded time avoids the issue.
How many work hours are in a year?
40 hours a week for 52 weeks is 2,080 hours. With two weeks off it is about 2,000 hours, the figure often used to turn a salary into an hourly rate.
Related tools
Accuracy note: Overtime and break rules follow US Department of Labor FLSA guidance. This is an estimate, not payroll or legal advice. Rules vary by state and country, so confirm with your employer or a payroll professional.
Content Lead, Anchor AI Tools, California, USA. Spotted an error? Email hello@anchoraitools.com and it will be checked and corrected. See our editorial standards.