Work Hours Calculator

What counts as a work hour

A work hour is the span between clock-in and clock-out, minus the breaks your employer does not pay. The math itself is small: end time minus start time, then subtract lunch. What trips people up is the format. Timesheets and payroll systems speak in decimal hours, while the clock on the wall speaks in hours and minutes, and the two get mixed up constantly. Seven hours and 30 minutes is 7.50 in decimal, but people write 7.30, and a 20 cent per hour error follows them all year.

The federal rule that defines the frame is the Fair Labor Standards Act. Under the FLSA, hours worked generally includes all time an employee must be on duty, on the premises, or at a prescribed workplace. Short breaks, usually 5 to 20 minutes, count as paid work time. A genuine meal period, 30 minutes or more where you are fully relieved of duty, does not have to be paid. That distinction is exactly what the lunch field in this calculator models.

Worked example: eight to four with a half hour lunch

Take a plain week. Monday through Thursday the worker clocks in at 8:00 a.m. and out at 4:00 p.m. with a 30 minute unpaid lunch. Friday is a short day, 8:00 a.m. to 2:30 p.m., same lunch. Here is each day:

Monday: 8:00 a.m. to 4:00 p.m. is 8 hours. Subtract the 30 minute lunch and the paid span is 7 hours 30 minutes, which is 7.50 decimal hours. Tuesday, Wednesday and Thursday come out the same. Friday: 8:00 a.m. to 2:30 p.m. is 6 hours 30 minutes, minus 30 minutes of lunch, leaves 6 hours even.

The weekly total is 36.00 paid hours, four under the 40 hour line. At $22 an hour the gross preview is 36 x 22 = $792 for the week. No overtime applies because nothing crossed the threshold.

Worked example: a week with overtime

Now push the same schedule later. Say the worker stays until 5:30 p.m. Monday through Friday, still with a 30 minute lunch. Each of those days is 9 hours on the clock, minus a half hour lunch, so 8.50 paid hours. Five of them is 42.50 hours for the week. The first 40 pay at the regular rate and the 2.5 above the line pay at time and a half.

At a $22 base rate the gross preview works out like this: 40 x 22 = $880 of regular pay. The overtime rate is 22 x 1.5 = $33 an hour, so 2.5 x 33 = $82.50. Total gross: $962.50. That $82.50 line is the number workers most often leave on the table, because a timesheet that rounds 42.50 down to 40 hides it.

The FLSA overtime threshold is a workweek, a fixed and regularly recurring 168 hour period of seven consecutive 24 hour days. Averaging hours across two weeks is not allowed: 46 hours in week one and 34 in week two still earns 6 hours of overtime in week one. State rules can sit on top of this; daily overtime after 8 hours exists in a few states, and California overtime is the well known case.

Decimal hours: the format payroll pays in

Payroll converts minutes to a fraction of an hour by dividing by 60. The quarter hour marks are the ones to memorize, because most timekeeping systems round to them: 15 minutes is 0.25, 30 minutes is 0.50, 45 minutes is 0.75. Anything else follows the same ratio. Twelve minutes is 12 / 60 = 0.20. Thirty eight minutes is 38 / 60 = 0.6333, which rounds to 0.63.

The common mistake is writing 7:38 as 7.38. That reading treats the minutes as a two digit decimal, so 7.38 hours is 7 hours and 22.8 minutes, about 15 minutes of paid time missing from every such day. Over a 260 day work year, a 15 minute daily error is about 65 hours, which at $22 an hour is $1,430.

Overnight shifts and crossing midnight

A night shift breaks the naive subtraction. From 10:00 p.m. to 6:00 a.m., subtracting 10 from 6 gives a negative number. The fix is to treat any end time earlier than the start time as the next day: add 24 hours to the end before subtracting. So 6:00 a.m. becomes 30:00, and 30:00 minus 22:00 is 8 hours.

With a lunch break the same rule holds after the subtraction. A 9:00 p.m. to 5:30 a.m. shift with a 30 minute meal is 8.5 hours on the clock minus 0.5, so 8.00 paid hours. The calculator applies this correction automatically, and it works for any span under 24 hours, which covers every legal shift.

Breaks the law says are paid

The FLSA does not require employers to give short breaks at all, but when short breaks of 5 to 20 minutes are offered, federal guidance counts them as hours worked and they must be paid. Meal periods are different: a bona fide meal period is 30 minutes or longer and the employee must be completely relieved of duty. If you are eating at the register or answering chat messages over a sandwich, that is work time and it belongs in the paid total.

Practical effect on the calculator: only unpaid meal minutes go in the lunch field. Two 15 minute breaks stay out of it, because they are paid. If your employer docked you 20 minutes for what was in fact a working lunch, your timesheet is understating your hours and this tool will show the gap when you compare the two.

Some states add their own layer, requiring a paid 10 minute rest break for every 4 hours worked, or a meal period after 5. The Department of Labor's break guidance and your state labor office are the references to check when a paystub looks short.

Overtime, the 40 hour week and pay preview

Federal overtime starts above 40 hours in a single workweek and pays at least 1.5 times the regular rate. The regular rate is not always the same as the hourly wage on the hiring sheet: nondiscretionary bonuses and shift differentials fold into it, which nudges the overtime rate up. For a plain hourly worker with no extras, the regular rate is the wage, so the math here matches the paycheck. The American Time Use Survey puts the average full time workday near 8.5 hours on days worked, which is why a 40 hour weekly line fits most schedules.

Gross pay preview with the example numbers: 42.50 hours at a $22 rate is 40 regular hours worth $880, plus 2.5 overtime hours worth $82.50, for $962.50 gross before taxes. Gross means before withholding, so the take home number is smaller. The preview in this calculator is gross, and it treats any hour above the threshold you set at 1.5 times the rate, which is the FLSA standard but not a universal one: some employers pay double time for holidays, and a few states extend overtime to daily thresholds.

Where the 47.00 row comes from: 40 x 22 = 880, and 7 overtime hours at 33 = 231, so 880 + 231 = 1,111.

Mistakes that make work hours come out wrong

The errors repeat from week to week, and they are all checkable:

• Writing 7:30 as 7.30 decimal. 7.30 hours is 7 hours 18 minutes. The right decimal is 7.50. This one mistake moves a weekly check by up to a few hours.
• Subtracting lunch twice. If the clock-out time already reflects walking out after lunch, the lunch field should be zero. Only subtract lunch when both clock times bracket it.
• Forgetting the overnight correction. A 10 p.m. to 6 a.m. span is 8 hours, not negative 16. Any end earlier than the start means the shift crossed midnight.
• Rounding too early. Convert each day to two decimals first, then add. Rounding each day to the nearest whole hour then adding can hide half an hour a week.
• Ignoring the overtime line. 41 hours earns 1 hour of overtime pay, not a flat weekly salary credit, unless an exemption applies.
• Counting a working lunch as unpaid. If duty continued through the meal, those 30 minutes are work time.

Compare your timesheet against the clock for two straight weeks and each of these will surface, because the totals will not match and the difference will be traceable to one of the six lines above.