How to calculate hours worked
Working out hours between two times takes three steps: subtract the start from the end, fix the result if the shift crosses midnight, then take off any unpaid break.
If the end time is earlier than the start: add 24 hours to the end time first
The tricky part is that time does not count in tens. An hour has 60 minutes, so you cannot subtract 8:45 from 17:15 like ordinary decimals. The easiest way by hand is to turn both times into minutes after midnight, subtract, and turn the answer back into hours and minutes. The calculator does exactly that, and it shows the working under every result.
Payroll usually needs decimal hours rather than hours and minutes, because a decimal can be multiplied by an hourly rate.
Pay = decimal hours × hourly rate
Worked examples
Example 1: a day shift with lunch. You start at 8:45 AM, finish at 5:15 PM and take an unpaid 30-minute lunch.
- In 24-hour time the shift runs from 8:45 to 17:15.
- 17:15 − 8:45 = 8 hours 30 minutes on the clock.
- 8:30 − 0:30 break = 8 hours 0 minutes, which is 8.00 decimal hours.
- At $18.50 an hour: 8.00 × 18.50 = $148.00.
Example 2: a night shift. You clock in at 10:00 PM and out at 6:30 AM, with a 45-minute unpaid break.
- The end time (6:30) is earlier than the start (22:00), so the shift ends the next day. Add 24 hours: 6:30 becomes 30:30.
- 30:30 − 22:00 = 8 hours 30 minutes.
- 8:30 − 0:45 = 7 hours 45 minutes, or 45 ÷ 60 = 0.75, so 7.75 decimal hours.
- At $22 an hour: 7.75 × 22 = $170.50.
Example 3: several shifts. A part-time worker has three shifts this week: 9:00 to 17:00 with 30 minutes off, 8:30 to 17:15 with 45 minutes off, and 22:00 to 6:30 with 30 minutes off.
| Shift | On the clock | Break | Paid time | Decimal |
|---|---|---|---|---|
| 9:00 – 17:00 | 8:00 | 0:30 | 7:30 | 7.50 |
| 8:30 – 17:15 | 8:45 | 0:45 | 8:00 | 8.00 |
| 22:00 – 6:30 | 8:30 | 0:30 | 8:00 | 8.00 |
| Total | 25:15 | 1:45 | 23:30 | 23.50 |
Switch the calculator to Several shifts to add up to five shifts like this. For a full Monday-to-Sunday week with overtime, the time card calculator is built for that job.
Minutes to decimal hours
Use this table to turn minutes into the decimal part of an hour. Values are rounded to two places, which is what most payroll systems use.
| Minutes | Decimal | Minutes | Decimal | Minutes | Decimal |
|---|---|---|---|---|---|
| 1 | 0.02 | 20 | 0.33 | 40 | 0.67 |
| 3 | 0.05 | 24 | 0.40 | 42 | 0.70 |
| 5 | 0.08 | 25 | 0.42 | 45 | 0.75 |
| 6 | 0.10 | 30 | 0.50 | 48 | 0.80 |
| 10 | 0.17 | 33 | 0.55 | 50 | 0.83 |
| 12 | 0.20 | 35 | 0.58 | 54 | 0.90 |
| 15 | 0.25 | 36 | 0.60 | 55 | 0.92 |
| 18 | 0.30 | 39 | 0.65 | 60 | 1.00 |
Notice that every 6 minutes is exactly a tenth of an hour. That is why some employers and lawyers bill in tenths.
A common mistake is reading decimal hours as hours and minutes. 8.30 hours is not 8 hours 30 minutes. It is 8 hours and 18 minutes, because 0.30 × 60 = 18. Eight and a half hours is 8.5.
12-hour and 24-hour times
The calculator accepts either format, because your device shows time boxes in its own style. If you are doing the sums by hand, convert to the 24-hour clock first: add 12 to any PM hour except 12 PM, and treat 12 AM as 0.
| 12-hour | 24-hour | 12-hour | 24-hour |
|---|---|---|---|
| 12:00 AM (midnight) | 00:00 | 12:00 PM (noon) | 12:00 |
| 6:30 AM | 06:30 | 1:00 PM | 13:00 |
| 9:00 AM | 09:00 | 5:30 PM | 17:30 |
| 11:45 AM | 11:45 | 10:00 PM | 22:00 |
Breaks: paid or unpaid?
Only take off breaks you are not paid for. Under the US Fair Labor Standards Act, short rest breaks of about 5 to 20 minutes count as hours worked and must be paid. A genuine meal period, normally 30 minutes or more, where you are completely relieved of duty, does not count. If you have to keep answering the phone at your desk while you eat, it is working time.
Rules differ by country and by state. Some US states require meal or rest breaks, and in the UK most workers are entitled to a 20-minute rest break when they work more than six hours (whether it is paid depends on the contract). Check your contract or local labour rules if you are unsure.
Rounding clock-in times
Many time clocks round punches. US Department of Labor rules allow employers to round to the nearest 5 minutes, tenth of an hour (6 minutes) or quarter hour (15 minutes), as long as the rounding is neutral over time, so workers are fully paid for the time they actually work.
With quarter-hour rounding, anything up to 7 minutes rounds back and 8 minutes or more rounds forward. Clocking in at 8:07 counts as 8:00, while 8:08 counts as 8:15. A shift from 8:07 to 4:53 PM is 8 hours 46 minutes in reality, but 8:00 to 5:00 after rounding, which is 9 hours. Choose a rounding option in the calculator to compare your real hours with what a rounding time clock would show.
Hours between two dates
Some jobs span more than one day: a 36-hour hospital shift, a long-haul drive, or the time between submitting and closing a support ticket. Pick Between dates, enter a start date and time and an end date and time, and the calculator counts whole days as 24 hours each and then adds the clock difference. For example, 9:00 AM on Monday to 5:30 PM on Wednesday is 2 × 24 + 8.5 = 56.5 hours.
These are wall-clock hours. If the clocks go forward or back for daylight saving time inside the period, the real elapsed time is one hour less or more.
Tips for accurate timesheets
- Record times as you go. Writing times down at the end of the week is where most errors creep in.
- Use decimal hours for pay, h:mm for people. Managers read 7:45 easily; payroll software wants 7.75.
- Do not round twice. If your time clock already rounds, enter the rounded times and set the calculator to no rounding.
- Check overnight shifts. If a night shift shows a tiny or huge number, an AM/PM mix-up is the usual cause.
- Keep the link. The address bar updates as you type, so you can bookmark or share the exact calculation.
Related tools
To add or subtract durations such as 2:45 + 1:30, use the time calculator. For a full week with overtime at time and a half, use the time card calculator. To turn hours and a rate into take-home pay after tax, try the paycheck calculator, and for counting days rather than hours, the date calculator.