Hours Calculator

How hours worked are calculated

The hours calculator turns each clock time into minutes after midnight, subtracts the start from the end, and then subtracts any unpaid break. If the end time is earlier than the start, the shift must have crossed midnight, so 24 hours (1,440 minutes) is added before the break comes off. The result is shown as hours and minutes (8:30) and as decimal hours (8.50), because timesheets and payroll systems use one or the other.

Worked example, day shift: 8:45 AM to 5:15 PM is 17:15 − 8:45 = 8 hours 30 minutes on the clock. Take off a 30-minute unpaid lunch and you've worked 8:00, or 8.00 decimal hours. Night shift: 10:00 PM to 6:30 AM is (6:30 + 24:00) − 22:00 = 8 hours 30 minutes; less a 30-minute meal break, that's 8:00 again. The "Show the math" panel under the result lays out the same steps with your own times.

The time inputs accept whatever format your device uses, 12-hour with AM/PM or 24-hour, and the result is the same either way. A break as long as the shift itself is flagged as an error rather than giving zero or negative hours.

If you add up a week by hand, total the hours and the minutes in separate columns, then carry every 60 minutes over as an hour. Monday 7:45, Tuesday 8:20 and Wednesday 6:50 give 21 hours and 115 minutes. That's 22 hours 55 minutes (22:55), or 22.92 decimal hours. Adding the clock figures as ordinary decimals (7.45 + 8.20 + 6.50 = 22.15) is a common timesheet error. Here it undercounts by more than half an hour, because the minutes column rolls over at 60, not 100.

Weekly time cards, overtime and gross pay

The time card mode totals up to seven days. It starts with a standard 9:00 to 5:30 Monday-to-Friday week with a 30-minute lunch, which is 8 hours a day and 40 a week. Edit or clear any day; a blank day is skipped, but a day with only a start or only an end time is flagged so a missing punch doesn't quietly vanish from the total.

Under the US Fair Labor Standards Act (FLSA), employees who aren't exempt must be paid at least one and a half times their regular rate for hours over 40 in a workweek. The workweek is any fixed, recurring 168-hour period the employer sets, so it doesn't have to run Monday to Sunday. Each week stands alone, so a 45-hour week can't be averaged with a 35-hour week. Federal law has no daily overtime, but some states do. California, for example, also pays overtime for hours over 8 in a workday. Turn the overtime option off if you're salaried-exempt, or if you only want a straight-time total.

Example: five 8-hour weekdays plus 5 hours on Saturday is 45 hours. At $20 an hour, that's 40 × $20 = $800 regular pay plus 5 × $30 = $150 overtime, so $950 gross. Without the overtime premium it would be $900. To see what share of your pay came from overtime, the Percentage Calculator does that in one step ($150 is about 15.8% of $950).

Minutes to decimal hours conversion table

Payroll software usually wants decimal hours, so minutes have to be divided by 60. A common mistake is to read 7:30 as 7.30: it is 7.5 hours. Use this table for quick conversions, rounded to two decimal places as most timesheets are.

To go the other way, multiply the decimal part by 60: 6.4 hours is 6 hours plus 0.4 × 60 = 24 minutes. Some employers track time in tenths of an hour (6-minute blocks) instead, so 0.1 hour is 6 minutes and 0.25 is 15 minutes.

Breaks and time rounding: what counts as hours worked

Only enter unpaid time in the break field. According to the US Department of Labor, short rest periods (usually 20 minutes or less) count as hours worked and must be paid. A bona fide meal period, typically 30 minutes or more, can be unpaid, but only if you're completely relieved of duty. Eating at your desk while answering the phone doesn't qualify. Federal law doesn't require employers to give breaks at all, though many states do.

Many time clocks round punches, commonly to the nearest 5, 6 or 15 minutes. Federal rules allow this as long as it averages out over time and doesn't consistently shortchange employees. If your pay stub doesn't match this calculator's total by a few minutes a day, rounding is the usual reason. Enter the rounded times to reproduce your employer's figure.

Overnight shifts, time zones and daylight saving time

Overnight shifts work without any extra input: 11 PM to 7 AM is read as 8 hours. Each row covers at most 24 hours, so a single shift longer than that should be split at midnight into two rows. To count calendar days rather than hours, for example the days between two pay dates, use the Date Calculator.

The calculator measures wall-clock time and doesn't know about daylight saving changes. On the night clocks spring forward, a shift from 10 PM to 6 AM is 7 real hours, not 8. On the night they fall back, the same shift is 9 real hours. Payroll should reflect the time actually worked, so adjust those two nights by an hour. The same goes for remote work across time zones: enter both times in the same time zone, ideally the one your employer uses for payroll.

Sources

The formulas on this page come from the published research below. Last updated October 10, 2026. This calculator gives estimates for general information. It isn't medical advice, so check anything important with a qualified professional.

1. U.S. Department of Labor, Wage and Hour Division. Fact Sheet #22: Hours Worked Under the Fair Labor Standards Act (FLSA).Used for: Paid short rest breaks vs. unpaid meal periods; overtime after 40 hours a week at 1.5×