Time Calculator
Add and subtract hours, minutes and seconds, find the time between two clock times with breaks and overnight shifts, total a weekly timesheet, or add a duration to a time of day. Results come in hours and minutes and in decimal hours.
Your result
Enter your times above to see the result.
Exact to the second, with no rounding unless shown. Decimal hours are rounded to two places for display. Check your employer’s rounding and break rules before using the figures for pay.
Why time sums feel awkward
Ordinary arithmetic works in tens. Time works in sixties for minutes and seconds, twenty-fours for hours, and sevens for days. That mix is why 1 hour 45 minutes plus 1 hour 30 minutes is 3 hours 15 minutes and not 2.75 or 3.15, and why a quick sum on a phone calculator often gives a confusing answer.
This calculator does the carrying for you. Put in your times, and it works in seconds behind the scenes so that nothing is lost, then gives you the answer in days, hours and minutes and also as decimal hours for timesheets and spreadsheets.
How to use this calculator
- Add or subtract: list durations with a plus or minus and get the total. Handy for adding up video lengths, journey legs or task times.
- Between two times: enter a start and an end time and any unpaid break to see how long the period is, including overnight.
- Timesheet: fill in each day’s start, end and break. You get daily hours, the weekly total, and a pay estimate if you add a rate.
- Clock time: start from a time of day and add or subtract hours and minutes to see what time it will be.
The formulas
Total seconds = days × 86,400 + hours × 3,600 + minutes × 60 + seconds
Decimal hours = hours + minutes ÷ 60 + seconds ÷ 3,600
Time between = end − start (add 24 hours if the end is earlier)
Hours worked = time between − unpaid break
Worked examples
Adding and subtracting
1 hour 30 minutes plus 2 hours 45 minutes minus 20 minutes. The minutes are 30 + 45 − 20 = 55, and the hours are 1 + 2 = 3, so the total is 3 hours 55 minutes, or 3.92 decimal hours.
A normal working day
Start 9:00, finish 17:30, 30 minutes unpaid break. The period is 8 hours 30 minutes, minus the break leaves 8 hours, so 8.00 decimal hours.
A night shift
Start 22:00, finish 06:30. The end is earlier than the start, so the shift crosses midnight and lasts 8 hours 30 minutes.
A weekly timesheet
Five days from 9:00 to 17:30 with a 30-minute break each is 8 hours a day, 40 hours in the week. At a rate of 18.50 an hour that is an estimated 740.00 before tax and deductions.
Minutes as decimal hours
Payroll and spreadsheet formulas usually need decimal hours. Divide the minutes by 60 to convert. The table shows the values you will use most.
| Minutes | Decimal hours | Minutes | Decimal hours |
|---|---|---|---|
| 5 | 0.083 | 35 | 0.583 |
| 10 | 0.167 | 40 | 0.667 |
| 15 | 0.25 | 45 | 0.75 |
| 20 | 0.333 | 50 | 0.833 |
| 25 | 0.417 | 55 | 0.917 |
| 30 | 0.5 | 60 | 1.0 |
So 7 hours 45 minutes is 7.75 hours. It is not 7.45.
Overnight shifts and midnight
A clock only shows 24 hours, so when a shift ends before it starts, the calculator treats the end time as the next day. That works for anything under a full day. For longer periods, such as a trip over several days, use the Add or subtract tab and enter the days directly, or use the date difference tool to count days between calendar dates.
Common mistakes
- Writing 1 hour 30 minutes as 1.30 and then treating it as a decimal. It is 1.5 hours.
- Adding minutes as if they went up to 100 instead of 60.
- Forgetting to take off an unpaid break when working out paid hours.
- Mixing up AM and PM, or 12:00 AM and 12:00 PM. Using 24-hour times avoids this.
- Rounding every day before totalling the week, which can add or lose minutes. Total first, then round.
Frequently asked questions
How do I add hours and minutes together?
Add the minutes first. If they come to 60 or more, carry each full 60 into the hours column. For 2 hours 45 minutes plus 1 hour 30 minutes, the minutes are 45 + 30 = 75, which is 1 hour 15 minutes, so the total is 2 + 1 + 1 = 4 hours 15 minutes. Time works in sixties, not hundreds, which is why it cannot be added like ordinary decimals.
How do I subtract time?
Subtract minutes from minutes and hours from hours, borrowing 60 minutes from the hours column when the minutes would go negative. 5 hours 20 minutes minus 2 hours 45 minutes is 2 hours 35 minutes. The Add or subtract tab does this for any list of values and shows the total in several formats.
How do I calculate the hours between two times?
Subtract the start time from the end time. From 9:00 to 17:30 is 8 hours 30 minutes. If the end time is earlier than the start time, the period crosses midnight, so add 24 hours: 22:00 to 06:30 is 8 hours 30 minutes. The Between two times tab handles overnight spans automatically and subtracts any unpaid break.
How do I convert hours and minutes to decimal hours?
Divide the minutes by 60 and add them to the hours. 7 hours 45 minutes is 7 + 45/60 = 7.75 hours. A common mistake is to write 1 hour 30 minutes as 1.30, when it is really 1.5. Payroll systems and spreadsheets usually need decimal hours, so the calculator shows both.
How do I calculate hours worked on a timesheet?
For each day, take the finish time minus the start time and subtract unpaid breaks, then add up the days. The Timesheet tab does this for up to 14 days at once, shows each day's hours and the total, and can multiply the total by an hourly rate for a rough pay estimate.
Does the calculator handle overnight shifts?
Yes. If the finish time is earlier than the start time, the calculator assumes the shift ends the next day. A shift from 22:00 to 06:00 is 8 hours. It does not handle shifts longer than 24 hours, since a clock time alone cannot tell the difference.
How do I add a duration to a clock time?
Use the Clock time tab. Enter a start time and the number of hours and minutes to add or subtract and you get the new time, with a note if it falls on the next or previous day. For example, 9:30 plus 8 hours 15 minutes is 17:45.
What is the difference between 12-hour and 24-hour time?
The 12-hour clock uses AM and PM and runs from 12:00 AM (midnight) to 11:59 PM, while the 24-hour clock runs from 00:00 to 23:59. 17:45 on the 24-hour clock is 5:45 PM. The calculator shows both for clock times.
How should I round hours for payroll?
It depends on your employer and local rules. Some pay to the exact minute, others round to the nearest quarter hour or tenth of an hour. This calculator gives exact figures, so check your employer's policy or your local labour regulations before rounding.
Can I use this for more than 24 hours?
On the Add or subtract tab, yes. Totals above 24 hours are shown as days, hours and minutes and also as total hours, so 30 hours appears as 1 day 6 hours and as 30 hours in total.
Is anything I type saved or sent anywhere?
No. The sums run in your browser and nothing you enter is uploaded or stored on our servers.
Related calculators
For counting working days between dates use the work days calculator. For the number of days between dates, or someone’s age, try the age and date calculator, and for converting a time between places, the time zone converter.