Duration calculator

How much time is that?

Find the time between two dates and clock times, add or subtract a duration, or total a list of hh:mm:ss times.

What to work out

Start date

Start time

24-hour clock, such as 9:30 or 17:45:10

End date

End time

Time between

1:00:00

The list adds up to 1 hr

The same length of time

Days: 1.3542
Hours: 32.5
Minutes: 1,950
Seconds: 117,000

Dates and times have no time zone, so a daylight-saving change in between is not counted.

How to use

Choose what to work out: the time between two moments, a moment plus or minus an amount of time, or the total of a list of durations.
Fill in the dates and times, or the amount, or the list. The answer updates as you type.

Common durations in seconds

Duration	Seconds
5 mins	300
15 mins	900
30 mins	1,800
45 mins	2,700
1 hr	3,600
1 hr, 30 mins	5,400

How it works

Time is counted in a mixed scale: 60 seconds make a minute, 60 minutes an hour and 24 hours a day. This tool turns every moment into a count of seconds, does the plain subtraction or addition and turns the result back into days, hours, minutes and seconds. A date is first counted in whole days along the calendar, so months of different lengths and leap years are handled for you.

To total durations such as 1:30:00 and 0:45:30, turn each into seconds (1 h = 3600 s, 1 min = 60 s): 5400 s and 2730 s add up to 8130 s, which is 2 h 15 min 30 s. The hours may go past 24, so a long list reads 26:05:00 rather than being wrapped into days.

Dates and times here have no time zone. Every day is exactly 24 hours, so a clock change for daylight saving time between the two moments is not counted, and the same goes for leap seconds.

Frequently asked questions

How do I add hours and minutes together?

Choose Total a list and type each duration as hours:minutes, for example 1:45 2:30. The total is 4:15.

How do I find how long a shift lasted?

Choose Time between, enter the start and end date and time. A night shift that crosses midnight just needs the next day's date for the end.

Does it count daylight saving time?

No. It works on clock times without a time zone, so a day always has 24 hours. If a clock change falls between your two moments, the real elapsed time differs by an hour.

Can I subtract a duration from a date?

Yes. Choose Add or subtract, pick Subtract and enter the days, hours, minutes and seconds.

Can I enter decimal hours in the list?

No. Use hours:minutes or hours:minutes:seconds; use the decimal-hours converter for decimal values.

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