How to calculate hours worked (with a full week example)

Calculating hours worked sounds trivial until a paycheck comes up short and nobody can say why. The method itself takes one line of arithmetic. The errors hide in the details: minutes treated like decimals, breaks deducted twice, night shifts that cross midnight. This guide walks through the whole process with real numbers you can check by hand, then covers the federal rules that decide which minutes count as paid time in the first place.

The formula for hours worked

Hours worked = end time - start time - unpaid breaks.

Take a standard office day: start at 9:00, finish at 17:30, 30 minutes of unpaid lunch. From 9:00 to 17:30 is 8 hours 30 minutes. Remove the 30 minute break and you get 8 hours net.

The reliable way to do this on paper is to convert everything to minutes first. 9:00 is minute 540 of the day, 17:30 is minute 1050. The difference is 510 minutes; subtract 30 for lunch and you have 480 minutes, which is exactly 8 hours. Working in minutes avoids the classic slip of subtracting 9:00 from 17:30 as if they were plain numbers and getting 8.30, which is not a duration.

How to convert minutes to decimal hours

Payroll systems multiply hours by an hourly rate, and that only works with decimal hours. 7 hours 30 minutes must become 7.5 rather than 7.30. The conversion is a single division: minutes / 60.

Round to two decimal places. Across a full week the rounding error stays under a minute, which no payroll system will notice.

Night shifts that cross midnight

A shift from 22:00 to 06:00 breaks naive subtraction: 6 minus 22 gives minus 16. The fix is to add 24 hours to the end time when it is smaller than the start time. So 06:00 becomes 30:00, and 30:00 minus 22:00 gives 8 hours. With a 45 minute break, the net is 7 hours 15 minutes, or 7.25 decimal hours.

Night work is also where 24-hour notation earns its keep. Time cards written 2200 to 0600 leave no AM or PM to misread, which is why hospitals and factories use them. If a timesheet format looks unfamiliar, convert the 24-hour time to standard time or keep the military time chart open while you fill it in.

What counts as paid time under the FLSA

The arithmetic only helps once you know which minutes belong in the total, and in the US that question has a federal answer. Fact Sheet #22 from the Department of Labor sets out the main cases:

• Short rest breaks are paid. Breaks of about 20 minutes or less count as hours worked. A coffee break never comes out of your total.
• Meal periods of 30 minutes or more can be unpaid, on one condition: you are fully relieved of duty. Eating at your desk while answering the phone is work time and must be paid.
• Waiting can be work. A firefighter playing checkers between alarms is engaged to wait, and those hours count.
• On-call time on the premises is work. On-call at home, where you only leave a number, in most cases is not.

Rounding has a rule of its own. Under 29 CFR 785.48, an employer may record start and stop times to the nearest 5 minutes, tenth of an hour or quarter hour, as long as the practice averages out and pays for all the time worked. Clocking 9:07 as 9:15 every single day fails that test, and the lost minutes add up to unpaid work. The same law also sets the 2.13 dollar cash wage for tipped jobs, covered in our guide to how much you should tip.

Common timesheet mistakes

Four errors account for most disputed paychecks:

• Minutes entered as decimals. Typing 8.45 for 8 hours 45 minutes pays 8.45 hours instead of 8.75. That shorts the employee 18 minutes per shift, roughly 1.5 hours over a five day week.
• Breaks deducted twice. If the time clock already splits the shift around lunch, deducting a lunch break again removes 30 minutes that were never counted.
• Paid breaks treated as unpaid. As the FLSA rules above spell out, short breaks stay in the total. Only genuine meal periods of 30 minutes or more come out.
• Rounding always in one direction. Neutral rounding goes both ways. A system that only ever rounds against the employee violates the averaging condition in 29 CFR 785.48.

A full week, fully worked out

A realistic week for an employee paid 20.00 per hour, with a 30 minute unpaid lunch on full days:

Add the decimal column: 8.00 + 8.00 + 7.50 + 8.00 + 5.33 = 36.83 hours. At 20.00 per hour, gross pay is 36.83 x 20.00 = 736.60. This week stays under the 40 hour federal threshold, so no overtime premium applies. Cross it and the hours beyond 40 are paid at 1.5 times the rate, a 50 percent bump that works like any percentage increase: 20.00 becomes 30.00.

Check Friday by hand to see the whole method in one line: 14:20 is minute 860, 9:00 is minute 540, no break, so 320 minutes, which is 5 hours 20 minutes, and 320 / 60 = 5.33 decimal hours. Every other row works the same way.

From weekly hours to a pay period

Paychecks rarely cover exactly one week. Biweekly pay covers 14 days and produces 26 checks a year; semimonthly pay covers the 1st through the 15th and the 16th through month end, for 24 checks. To reconcile a stub, add the daily totals for the exact date range on it. Counting the days in an odd period is a job for the date calculator.

One trap in longer periods: overtime is computed per workweek even when the check covers two. Working 45 hours one week and 35 the next averages to 80 across a biweekly check, yet the 5 hours over 40 in week one still carry the 1.5x premium.

How do I add up hours and minutes on a timesheet?

Convert each day to minutes before adding, because 60 minutes carry into an hour where 100 would in normal addition. For 7:45 plus 8:20: 465 + 500 = 965 minutes, which is 16 hours 5 minutes. For payroll, divide by 60 instead: 965 / 60 = 16.08 decimal hours. Adding the raw clock numbers gives 15:65, and fixing that by hand is where sums drift. Totaling five or six shifts is exactly the tedious step the hours calculator automates.

Are 15 minute breaks paid?

Under federal law, yes. The Department of Labor counts short rest breaks, usually 20 minutes or less, as hours worked, so a 15 minute coffee break stays in your paid total. Meal periods are different: a break of 30 minutes or more can be unpaid, provided you are fully relieved of duty. A lunch spent covering the phone at your desk fails that condition and must be paid. Several states add their own mandatory break rules on top of the federal floor.

What is 7.75 hours in hours and minutes?

7 hours 45 minutes. Multiply the decimal part by 60 to get the minutes: 0.75 x 60 = 45 minutes. The pairs worth memorizing run in quarters: 0.25 = 15 min, 0.50 = 30 min, 0.75 = 45 min. For anything else, the same multiplication works: 7.9 hours is 7 hours plus 0.9 x 60 = 54 minutes. Going the other way, divide the minutes by 60, so 7:45 becomes 7.75.

Is timesheet rounding legal?

Rounding itself is legal under 29 CFR 785.48: employers may record times to the nearest 5 minutes, tenth of an hour or quarter hour. The condition is that the practice must average out over time so employees get paid for all the time they worked. Rounding that only ever favors the employer, like recording 8:53 as 9:00 while recording 17:07 as 17:00, breaks that condition. Your own log of exact times is the evidence that shows the pattern.

How do I calculate overtime pay?

Under the FLSA, hours beyond 40 in a single workweek are paid at 1.5 times the regular rate. Work 44 hours at 20.00 per hour and the check splits in two parts: 40 x 20.00 = 800.00, plus 4 x 30.00 = 120.00, for a total of 920.00. The workweek is the unit that matters; averaging across a biweekly period is not allowed. Some states add daily overtime on top of the federal weekly rule, so a long single day can trigger the premium even in a short week.