The short answer
- Subtract the start from the finish; if the minutes go negative, borrow 60 from the hours.
- If the finish is earlier than the start, the time runs past midnight: add 24 hours to the finish.
- Decimal hours = minutes ÷ 60, so 7 hours 45 minutes is 7.75.
- Take unpaid breaks off the total before working out pay.
Hours between two times
Write both times in the 24-hour clock, then take the start from the finish. Do the minutes first. If the finish minutes are smaller than the start minutes, add 60 to them and take 1 from the hours.
- Minutes30 − 030
- Hours17 − 98
Shifts past midnight
When the finish time is earlier than the start, the shift has crossed midnight. Add 24 hours to the finish time, then subtract as usual. The calculator does this automatically whenever the finish is at or before the start.
- 06:00 + 24 hours30:00
- 30:00 − 22:008:00
- Less the break−0:45
Shifts over 24 hours
A finish time alone cannot show a shift longer than a day. For those, add up the hours of each day with “Add up hours and minutes”.
Taking off breaks
Enter any unpaid break in minutes and the calculator takes it off. A long day shift from 07:30 to 19:30 with a 60-minute break is 12 hours on site but 11 hours worked. Paid breaks should not be taken off, so leave the break at 0 if yours is paid.
Hours and minutes to decimal hours
Payroll systems and many timesheets use decimal hours, where 0.5 is half an hour. To convert, divide the minutes by 60 and add them to the hours. To go back, multiply the decimal part by 60.
| Minutes | Decimal |
|---|---|
| 5 | 0.08 |
| 10 | 0.17 |
| 15 | 0.25 |
| 20 | 0.33 |
| 25 | 0.42 |
| 30 | 0.50 |
| 40 | 0.67 |
| 45 | 0.75 |
| 50 | 0.83 |
| 55 | 0.92 |
The timesheet calculator does this for a whole week, day by day, with overtime.
The 7.30 trap
- Means
- 7 hours 30 minutes
- Decimal
- 7.50
- Means
- 7 hours 18 minutes
- Decimal
- 7.30
Writing 7.30 on a decimal timesheet when you mean half past seven loses 12 minutes of pay. Always check which format the form expects.
Adding up hours and minutes
Add the hours and the minutes separately, then turn each 60 minutes into an hour. To take time away, subtract the minutes first, borrowing an hour if needed. In the calculator, start a line with a minus to take it away.
- 7:30 + 8:1515:45
- 15:45 − 0:4515:00
From a day to a week and a year
Multiply a day’s hours by the days you work. Five 8-hour days make 40 hours a week, and 52 weeks of that is 2,080 hours a year. A 9-to-5 day with a 30-minute unpaid lunch is 7 hours 30 minutes, or 37 hours 30 minutes over five days. The calculator shows a day, a week, an average month (52 weeks ÷ 12) and a year.
Working out pay
Pay is decimal hours × hourly rate. Use decimal hours, not hours and minutes, or the answer will be wrong.
- Decimal hours8.00
- × £12.71£101.68
This is pay before tax. Choose £, $ or € under More options. To see holiday entitlement for your hours, try the holiday entitlement calculator.
24-hour and 12-hour clocks
The calculator reads both. In the 12-hour clock, 12am is midnight and 12pm is midday, so a shift from 9pm to 5am is 21:00 to 05:00 in the 24-hour clock. You can type 09:00, 9.30, 1730 or 5:30pm, and choose how times are shown under More options.
Breaks and working hours rules
In the UK, adult workers usually have the right to one uninterrupted 20-minute rest break if they work more than 6 hours a day, and it does not have to be paid. Most workers cannot be made to work more than 48 hours a week on average, normally over 17 weeks, unless they opt out.
In the US, the federal rule is that most hourly employees get overtime at one and a half times their regular rate for hours over 40 in a workweek. Contracts and local laws can give more.
Times in a spreadsheet
Spreadsheets store times as fractions of a day. With a start in A1 and a finish in B1, =MOD(B1-A1, 1) gives the time between them, even past midnight. Format the cell as [h]:mm to show totals over 24 hours, and multiply by 24 to get decimal hours.
Common mistakes
- Subtracting times as decimals, such as 17.30 − 9.45 = 7.85, instead of 7 hours 45 minutes.
- Forgetting that a night shift crosses midnight.
- Taking off a paid break, or forgetting an unpaid one.
- Rounding each day before adding, which can add up to several minutes a week.
For days rather than hours, use the date calculator.