How to calculate hours worked: breaks, decimal hours and overnight shifts

The basic calculation

For each day, take the clock-out time, subtract the clock-in time, then subtract any unpaid break. Work in hours and minutes, or convert both times to minutes after midnight, which avoids most mistakes.

Use the 24-hour clock if you can. 4:30 PM is 16:30, so a shift from 8:00 to 16:30 is 8 hours 30 minutes on the clock. Take off a 30-minute unpaid lunch and 8 hours are paid. If the minutes do not subtract, borrow an hour: 17:10 − 8:45 is 16:70 − 8:45, which is 8 hours 25 minutes.

Hours worked = End time − Start time − Unpaid break In minutes: (End hour × 60 + End minutes) − (Start hour × 60 + Start minutes) − Break minutes

Which breaks to subtract

Federal law does not require employers to give lunch or coffee breaks. But when breaks are given, the Fair Labor Standards Act rules on hours worked decide whether the time is paid.

Short rest breaks, usually about 5 to 20 minutes, are customarily paid and count as hours worked under 29 CFR 785.18. Do not subtract them. A bona fide meal period is not work time under 29 CFR 785.19, but only if the employee is completely relieved from duty to eat a regular meal. Ordinarily 30 minutes or more is long enough. An employee who must stay at their desk answering the phone, or watch a machine while eating, is working and must be paid for that time.

Many states set their own meal and rest break rules, which can be stricter. Check your state labor department before deciding a break is unpaid.

• Subtract: a 30-minute lunch when the employee is free to leave the work station and do nothing for the business.
• Do not subtract: a 10 or 15-minute coffee break, a lunch eaten while covering the counter, or a meal break cut short by work.

Convert minutes to decimal hours

A clock shows hours and minutes, but pay is hours times a rate, so payroll needs decimal hours. Divide the minutes by 60 and add them to the whole hours. 7 hours 45 minutes is 7 + 45 ÷ 60 = 7.75 hours. Writing it as 7.45 underpays by 18 minutes.

To go the other way, multiply the decimal part by 60: 8.2 hours is 8 hours and 0.2 × 60 = 12 minutes.

Decimal hours = Hours + Minutes ÷ 60 Minutes = Decimal part × 60

Overnight shifts that cross midnight

When a shift ends the next day, the end time looks earlier than the start, and simple subtraction gives a negative number. Add 24 hours to the end time first. A shift from 22:00 to 06:20 becomes 30:20 − 22:00 = 8 hours 20 minutes. Take off a 30-minute meal break and 7 hours 50 minutes are paid.

Our timesheet calculator does this automatically and records the whole shift on the day it started. For overtime, though, hours belong to the workweek in which they are actually worked. If a night shift runs past the moment your workweek starts, for example midnight on Saturday, split the hours between the two weeks.

If End is earlier than Start: Hours worked = (End + 24:00) − Start − Unpaid break

Worked example: a week at a café

A café worker earns $18 an hour. Their clock punches for the week are below, with a 30-minute unpaid lunch most days, a 45-minute one on Wednesday and none on the short Saturday shift. Friday is a night shift baking for the weekend.

Add the minutes for the whole week before converting: 465 + 480 + 510 + 490 + 470 + 315 = 2,730 minutes, which is 45 hours 30 minutes, or 45.5 decimal hours.

• Regular pay: 40 hours × $18 = $720.00.
• Overtime: 5.5 hours × $27 (1.5 × $18) = $148.50.
• Total gross pay for the week: $868.50.

Rounding clock times: what US law allows

Time clocks are not required, and employers do not have to pay for time when an employee clocks in early or stays late without doing any work. Many employers round punches to make the numbers easier. Under 29 CFR 785.48(b), the Department of Labor accepts rounding to the nearest 5 minutes, the nearest tenth of an hour (6 minutes) or the nearest quarter hour, as long as it does not, over time, fail to pay employees for all the time they actually worked.

In practice that means rounding to the nearest increment, both up and down, for starts and finishes alike. With quarter-hour rounding, 1 to 7 minutes past rounds down and 8 to 14 minutes past rounds up. Rounding that always favours the employer is not neutral. Rounding starts up and finishes down so the worker loses just 7 minutes a day in total costs a worker on $18 an hour about $525 over 250 working days.

Some states have stricter rules, and recording exact times is always the safest choice.

From weekly hours to overtime

Federal overtime is counted per workweek, a fixed and recurring 168-hour period that you choose and keep. Add up all hours worked in that workweek, including paid rest breaks, then pay at least 1.5 times the regular rate for every hour over 40. You cannot average two weeks: 35 hours one week and 45 the next means 5 overtime hours in the second week.

Some states, such as California, also pay overtime by the day, and bonuses can raise the regular rate. Our guide to overtime pay covers those rules. Once you have total hours, the overtime calculator splits them into regular and overtime pay.

Frequently asked questions

Sources

• 29 CFR 785.48, Differences between clock records and actual hours worked (rounding)
• 29 CFR 785.19, Meal periods
• US Department of Labor: Breaks and meal periods

General information, not financial, tax or legal advice. Rules change and differ by place; check with the official source or a qualified adviser before you act.