How to Calculate Overtime in Decimal Hours

Under the federal Fair Labor Standards Act (FLSA), most hourly employees must be paid 1.5 times their regular rate for every hour worked over 40 in a single workweek. A workweek is seven fixed 24-hour periods, defined by the employer: Sunday-to-Saturday and Monday-to-Sunday are both common. The 40-hour threshold applies to each workweek on its own. It never resets mid-week, and hours cannot be carried into the next week to avoid overtime.

Overtime is a threshold question: is the week over 40.00 hours or not? In hours-and-minutes form that comparison is annoying (is 40h 50m over? by how much?). In decimal form it is a subtraction. Convert each day, add the week, and read the answer straight off:

overtime hours = weekly decimal total − 40.00

A week that adds to 43.50 decimal hours has 3.50 overtime hours. There is no ambiguity about where the threshold was crossed or by how much.

Take a week at $20.00 an hour with the following decimal days: Monday 8.50, Tuesday 9.25, Wednesday 8.00, Thursday 10.00, Friday 8.25. The total is 44.00 hours.

Regular hours: 40.00 × $20.00 = $800.00. Overtime hours: 4.00, paid at 1.5 × $20.00 = $30.00 an hour, so 4.00 × $30.00 = $120.00. Gross pay for the week: $920.00. Two lines of multiplication once the week is in decimal form.

Real timesheets are rarely round. Say the same $20.00-an-hour week adds up to 42.17 hours. The overtime is 2.17 hours, and overtime pay is 2.17 × $30.00 = $65.10. Regular pay is 40.00 × $20.00 = $800.00, so the week grosses $865.10.

The 0.17 is no typo: 0.17 decimal hours is about 10 minutes (0.17 × 60), so the week was 42 hours 10 minutes. Payroll systems keep the decimal all the way through the multiplication, which is exactly why they store hours that way.

Time-and-a-half is computed on your regular rate, not necessarily your stated hourly wage. If you earn shift differentials (nights, weekends), commissions, or non-discretionary bonuses, those amounts generally fold into the regular rate first, and the overtime premium is 1.5 times the higher figure. A $18.00 wage with a $100 weekly bonus across 45 hours has a regular rate of (18 × 45 + 100) ÷ 45 = $20.22, so overtime pays $30.33 an hour, not $27.00.

Federal law counts overtime by the week, but several states add daily triggers. California is the best known: hours over 8 in a day earn overtime, hours over 12 earn double time, and a seventh consecutive workday triggers overtime too. Colorado, Alaska, and Nevada have their own daily rules. If you work in one of these states, convert each day to decimal hours and check the day total as well as the week total.

Averaging two weeks. A biweekly total of 80 hours does not cancel overtime earned in week one. If week one was 44.00 and week two was 36.00, you are owed 4.00 overtime hours for week one regardless of the two-week total.

Unpaid prep and cleanup. Time spent booting a register, stocking, or traveling between sites during a shift is generally work time and counts toward the 40.

Working through lunch. If 30 minutes are auto-deducted but you actually worked, the week is 2.50 hours higher over five days, which can be the difference between 39.50 and 42.00.

Pre-shift waiting. If you must be present and cannot use the time freely, it is usually compensable even before the shift officially starts.

Federal law requires only time-and-a-half over 40 hours. Double time (2.0 times your rate) is not required by the FLSA at all; it exists where union contracts, state rules, or employer policy create it. California is again the exception, with double time over 12 hours in a day. Working on a holiday is paid at your regular rate under federal law unless a contract or policy says otherwise, and the hours still count toward the weekly 40.

Compensatory time off instead of overtime pay is generally not permitted for private employers; it is a public-sector arrangement. If a private employer offers “comp time” in place of overtime, the hours still legally belong on the paycheck. In decimal terms: a 45.00-hour week owes 5.00 hours at 1.5 times the rate, not 5.00 hours of vacation.

Pay stubs list hours in decimal form. To audit one, convert your own daily records the same way (each day as decimal hours, summed per week), then compare week by week. Any week over 40.00 should show a separate overtime line at 1.5 times your regular rate. If the stub shows a lump sum, divide gross pay by an implied blended rate as a rough check, and ask payroll for the breakdown when the numbers do not reconcile.

This article is general information about how the math works, not legal advice. For a specific dispute, your state labor agency or an employment lawyer is the right resource.