Step by step: how to calculate hours worked in a day

Here is the method payroll departments use. It works for any shift, and it avoids the most common errors.

1. Write both times in 24-hour format. Add 12 to any PM hour except 12 PM. So 5:30 PM becomes 17:30, and 1:15 PM becomes 13:15. Morning times stay the same, except 12 AM, which is 0:00. This removes all AM and PM confusion.
2. Subtract the start time from the end time. Subtract the hours from the hours and the minutes from the minutes. 17:30 − 8:00 = 9 hours 30 minutes.
3. Subtract unpaid breaks. Take off your unpaid meal break, if you had one. 9:30 − 0:30 = 9 hours 0 minutes. Short paid rest breaks stay in.
4. Convert the minutes to decimal hours. Divide the minutes by 60 and add them to the hours. 9 hours 0 minutes = 9.00 hours. 7 hours 45 minutes = 7 + 45 ÷ 60 = 7.75 hours.

Repeat for every day, then add the daily totals to get your weekly hours. It is easiest to add in hours and minutes first, then convert the weekly total to decimal once.

When the minutes do not subtract: borrowing an hour

Sometimes the end minutes are smaller than the start minutes. Say you worked from 8:40 AM to 4:15 PM. In 24-hour time, that is 16:15 − 8:40, and you cannot take 40 minutes from 15.

Borrow one hour from the end time and add it as 60 minutes. 16:15 becomes 15:75. Now subtract: 15:75 − 8:40 = 7 hours 35 minutes. In decimal, that is 7 + 35 ÷ 60 = 7.58 hours.

Another way that some people find easier: count up from the start time. From 8:40 to 9:00 is 20 minutes. From 9:00 to 16:00 is 7 hours. From 16:00 to 16:15 is 15 minutes. Add them: 7 hours 35 minutes.

Overnight shifts that cross midnight

If your shift ends the next day, the end time will look smaller than the start time. For a shift from 10:00 PM to 6:30 AM, add 24 hours to the end time before subtracting:

Then take off any unpaid break. With a 30-minute meal break, the shift is 8 hours, or 8.00 decimal hours. Under federal law, all hours of a shift that starts on one day and ends on the next usually count in the workweek where the shift started, unless your employer has a different set policy.

Worked example: a full week on a time card

Here is a realistic week for an hourly worker who takes different lunch breaks each day:

Adding the hours and minutes: 7 + 8 + 9 + 7 + 7 = 38 hours, and 45 + 0 + 15 + 25 + 30 = 115 minutes, which is 1 hour 55 minutes. The week totals 39 hours 55 minutes, or 39.92 decimal hours. At $20 an hour, that is 39.92 × $20 = about $798.33 before taxes.

Now say the same worker also comes in on Saturday from 9:00 AM to 1:00 PM. That adds 4 hours, for a total of 43 hours 55 minutes. The first 40 hours are paid at $20, or $800. The other 3.92 hours are overtime at $30 an hour (1.5 × $20), or $117.50. Gross pay rises to $917.50. Our guide on how to calculate overtime pay covers the overtime part in detail.

Minutes to decimal hours: the chart

Payroll systems and most pay stubs show hours as decimals. This is where many people make a costly mistake: 8 hours 30 minutes is 8.5 hours, not 8.3. The part after the decimal point is a fraction of an hour, not a count of minutes.

Why it matters: if you write 8 hours 30 minutes as 8.3 instead of 8.5, you lose 0.2 hours, or 12 minutes. At $20 an hour, that is $4 a day, $20 a week and about $1,040 a year. Going the other way, you can turn decimals back into minutes by multiplying by 60: 0.75 × 60 = 45 minutes.

What counts as hours worked under federal law

The Fair Labor Standards Act (FLSA) decides which time must be paid for most U.S. hourly workers. The general rule is that any time your employer requires you to be on duty, on the premises or at a set workplace counts. Some specific situations:

Federal law does not require employers to give breaks at all. Many states do. California, for example, requires a 30-minute meal break for shifts over 5 hours and a paid 10-minute rest break for every 4 hours worked. Check your state labor department for your local rules.

How time clock rounding affects your hours

Many employers round clock punches instead of paying to the exact minute. Federal rules allow rounding to the nearest 5 minutes, 6 minutes (one tenth of an hour) or 15 minutes, as long as it is neutral and does not always favor the employer.

With 15-minute rounding, the 7-minute rule applies. Punches 1 to 7 minutes past a quarter hour round down, and 8 to 14 minutes round up. Clocking in at 8:07 counts as 8:00, while 8:08 counts as 8:15. If you clock out at 5:07 PM, it counts as 5:00, but 5:08 counts as 5:15.

Over a year, rounding should roughly even out. If your rounded hours are always lower than your real hours, write down your exact times and compare. The time card calculator has buttons for 5, 6 and 15-minute rounding so you can see both numbers side by side.

From hours worked to your paycheck

Once you know your weekly hours, three more numbers decide what you take home:

• Regular pay: hours up to 40 × your hourly rate.
• Overtime pay: hours over 40 in the workweek × 1.5 × your rate. A few states, including California, also pay daily overtime. The overtime pay calculator works this out in seconds.
• Taxes and deductions: federal income tax, 7.65% for Social Security and Medicare, state tax and any 401(k) or insurance. The paycheck calculator turns your gross pay into take-home pay.

To see what your usual week adds up to over a whole year, use the hourly to salary calculator. A steady 37.5-hour week at $20 an hour, for example, is $750 a week, or $39,000 a year before taxes.

Tips for tracking your hours accurately

• Keep your own record. Write down your in and out times each day, or take a photo of the time clock. It takes seconds and is your best proof if a paycheck looks wrong.
• Log breaks as they happen. Note when you leave and return from lunch, especially if you get interrupted by work during the break.
• Check every pay stub. Compare the hours on your stub with your own record. Mistakes are easier to fix within the same pay period.
• Know your workweek. Overtime is based on a fixed 7-day workweek set by your employer, which may not run Monday to Sunday.
• Keep records for at least two years. Federal wage claims can generally be filed up to two years back, or three years for willful violations.

Frequently asked questions

Sources

Rules on hours worked, breaks, travel and on-call time are from the U.S. Department of Labor’s Fact Sheet #22: Hours Worked Under the FLSA and the federal regulations at 29 CFR Part 785, including the rounding rule in section 785.48. Overtime rules are from the Department of Labor’s overtime pay guidance.