How to Calculate Hours Worked and Overtime on a Time Card
Adding up a week of clock-in and clock-out times by hand is where payroll mistakes start: minutes that don't add like decimals, unpaid breaks forgotten, shifts that cross midnight. Here's how to get it right.
Hours for one shift
hours = clock-out − clock-in − unpaid break. 9:00 to 17:30 with a 30-minute lunch = 8 hours. A night shift from 22:00 to 06:30 with a 30-minute break is also 8 hours — the time card calculator handles crossing midnight automatically.
Minutes to decimal hours
Payroll systems usually want decimal hours. Divide minutes by 60:
| Minutes | Decimal |
|---|---|
| 15 | 0.25 |
| 30 | 0.50 |
| 45 | 0.75 |
| 20 | 0.33 |
So 7 h 45 min is 7.75 hours, not 7.45 — a mistake that underpays every week.
Overtime
Under the US federal rule (FLSA), non-exempt employees earn at least 1.5× their regular rate for hours over 40 in a workweek. Some states, such as California, also have daily overtime (over 8 hours in a day). Other countries set their own limits.
Example: Monday–Thursday 9 hours, Friday 8 hours → 44 hours. With a 40-hour weekly limit, that's 40 regular + 4 overtime. At $20/hour: 40 × $20 + 4 × $30 = $920 gross.
When both a daily and a weekly limit apply, the calculator counts daily overtime first and then weekly overtime on the remaining regular hours, so no hour is counted twice.
Keep a record
Download the week as CSV for your records. Your entries stay in your browser only. To compare an hourly wage with a salaried offer, use the hourly to salary calculator.