Time Duration Calculator
Find the exact time between two times or dates, add or subtract hours and minutes, or add up a list of durations.
Results
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Enter your numbers to see the answer.
Duration
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Decimal hours
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Total minutes
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Total seconds
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Breakdown
How it's worked out
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How to use the time duration calculator
- Time between: enter a start time and an end time. Add dates if the period spans more than one day, such as a trip from Friday evening to Sunday afternoon.
- Add or subtract time: enter a start time (and a date if you like), choose Add or Subtract, then enter the days, hours, minutes and seconds to move by.
- Add up durations: enter up to six durations, such as the lengths of several videos, tasks or laps, to get the total.
Results update as you type, and seconds are optional everywhere.
How the calculation works
Every time is first turned into seconds after midnight: hours × 3,600 + minutes × 60 + seconds. The calculator then subtracts (or adds) and turns the answer back into hours, minutes and seconds.
Duration = (end date and time) − (start date and time)
With no dates, both times are on the same day, and if the end time is earlier the calculator adds 24 hours to it, because the period must have crossed midnight. Decimal hours are the total minutes divided by 60.
Worked examples
- A work shift: 9:15 AM to 5:45 PM is 555 to 1,065 minutes after midnight. 1,065 − 555 = 510 minutes = 8 hours 30 minutes = 8.5 decimal hours.
- A night shift: 10:30 PM to 1:15 AM. The end is earlier, so add 24 hours: 25:15 − 22:30 = 2 hours 45 minutes.
- Adding time: 10:00 PM plus 5 hours 30 minutes is 27:30, which is 3:30 AM on the next day.
- A total: 1:30 + 2:45 + 0:45 = 4 hours 120 minutes = 5 hours exactly.
A common timesheet mistake
Hours and minutes are not decimals. A shift of 7:45 is 7 hours 45 minutes, which is 7.75 hours, not 7.45. Entering 7.45 on a timesheet that expects decimal hours would lose 18 minutes of pay. The calculator shows every duration both ways, as hours:minutes:seconds and as decimal hours, so you can copy whichever one your form asks for.
Time unit conversions
| Period | Hours | Minutes | Seconds |
|---|---|---|---|
| 1 minute | 0.0167 | 1 | 60 |
| 1 hour | 1 | 60 | 3,600 |
| 1 day | 24 | 1,440 | 86,400 |
| 1 week | 168 | 10,080 | 604,800 |
| 30 days | 720 | 43,200 | 2,592,000 |
Frequently asked questions
How do I calculate the time between two times?
Convert both times to minutes after midnight, subtract the start from the end, and convert back to hours and minutes. From 9:15 AM (555 minutes) to 5:45 PM (1,065 minutes) is 510 minutes, which is 8 hours 30 minutes.
How do I work out time that goes past midnight?
If the end time is earlier than the start time, add 24 hours to the end time before subtracting. 10:30 PM to 1:15 AM is (1:15 + 24:00) − 22:30 = 2 hours 45 minutes. The calculator does this automatically when you leave the dates empty.
How do I add hours and minutes to a time?
Add the minutes first and carry any 60 minutes over as an hour, then add the hours and carry any 24 hours over as a day. 10:00 PM plus 5 hours 30 minutes is 3:30 AM the next day. Use the "Add or subtract" tab to do this with dates as well.
How do I convert hours and minutes to decimal hours?
Divide the minutes by 60 and add them to the hours. 8 hours 30 minutes is 8 + 30 ÷ 60 = 8.5 hours, and 2 hours 45 minutes is 2.75 hours. Decimal hours are what payroll and billing systems usually ask for.
Does the calculator allow for daylight saving time?
No. It measures clock time, the same way you would read two clocks on the wall. If a daylight saving change happens between your start and end, the real elapsed time is one hour more (in autumn) or one hour less (in spring) than the result.