What the time duration calculator does
It finds the elapsed time between two times. In the two times mode you enter a start and an end time on the same day, or overnight when the end time is earlier, like a shift from 10 PM to 6 AM. In the dates mode you enter two full dates with times, so the difference can span days, months or years.
For a full week of shifts with breaks and overtime, the Hours Calculator adds up each day for you.
The result is shown as hours, minutes and seconds (h:mm:ss), in words, as decimal hours for timesheets and invoices, and as total minutes and total seconds. A small extra box adds or subtracts hours and minutes from a clock time, for example to find when a 7 hour 30 minute job started at 9:45 AM will end.
How the duration is calculated
Both times are turned into seconds since midnight, subtracted, and the difference is split back into hours, minutes and seconds. 1:20:45 PM to 4:05:10 PM is 2 hours 44 minutes 25 seconds, or 2.74 hours.
Examples
- Work day: 8:30 AM to 5:15 PM is 8 hours 45 minutes, or 8.75 decimal hours.
- Overnight: 11:00 PM to 7:30 AM is 8 hours 30 minutes.
- Race or workout: start at 7:02:15, finish at 8:49:03, elapsed time 1:46:48.
- Across dates: from Friday 6:00 PM to Monday 8:00 AM is 62 hours, or 2 days 14 hours.
Time differences by hand
When the end minutes are smaller than the start minutes, borrow 60 minutes from the hours. For 4:10 minus 1:45, write 4:10 as 3:70, then 3:70 minus 1:45 is 2:25. For times past midnight, add 24 hours to the end time first: 2:00 AM becomes 26:00, and 26:00 minus 22:00 is 4 hours.
How to use the time duration calculator
- 1Pick two times, or two dates and times if the period spans more than one day.
- 2Enter the start and the end. Seconds are optional, and the 12 h or 24 h switch only changes how times are shown.
- 3Read the duration, then copy it with the totals, or use the box below the result to add or subtract time from a clock time.
Frequently asked questions
How do I calculate the time between two times?
Subtract the start time from the end time. If the minutes of the end time are smaller, borrow an hour: 5:15 PM minus 9:40 AM is 16:75 minus 9:40, which gives 7 hours 35 minutes. The calculator does this for you, down to the second.
What if the end time is after midnight?
In the two times mode, an end time that is earlier than the start time is read as the next day. 10:30 PM to 2:15 AM is 3 hours 45 minutes. For periods longer than a day, switch to the dates and times mode and enter both dates.
How do I turn a duration into decimal hours?
Divide the minutes by 60 and the seconds by 3,600, then add them to the hours. 2 hours 15 minutes is 2 + 15 ÷ 60 = 2.25 hours. The calculator shows decimal hours, total minutes and total seconds next to the h:mm:ss result.
Does daylight saving time change the result?
The result is the difference between the clock times you enter. If a period with two dates crosses a daylight saving change in your time zone, one hour more or less actually passes, and the calculator tells you the real elapsed time below the result.
Can I add hours and minutes to a time?
Yes. Use the add or subtract box under the result: enter a time, choose plus or minus and type the hours and minutes. 9:45 AM plus 7 hours 30 minutes is 5:15 PM. If the result passes midnight, the calculator says how many days later or earlier it is.