# How do I calculate a time delta in my Google Spreadsheets?

`````` Date        | Start time  | End time    | Minutes
------------+-------------+-------------+-----------
1/11/2012   | 11:39       | 12:41       | ?!
------------+-------------+-------------+-----------
|             |             |
``````

Right now if I fill in the number of minutes between the two times of day by hand. Is there a straight-forward way to calculate a time delta and have the spreadsheet do it for me?

-
Hi Stefano, perhaps you can take some time and evaluate the answers given. – Jacob Jan Tuinstra Aug 2 '13 at 18:58
@jacob As far as I can work out, my answer still works. I'll try to clarify and improve it a bit. – Stefano Palazzo Aug 5 '13 at 6:49

Google has added a new number format called Duration. Set your start and end fields to `Format -> Number -> Time` and your calculation field to `Format -> Number -> Duration`

Once you have done that you can subtract the fields to get the difference as noted by Stefano Palazzo in his answer.

-

Yes, If your time fields are properly formatted (click Format → Number → Time) you can just add and subtract times:

``````=C2-B2
``````

or

21:58:00 - 20:44:00 = 1:14:00

This will give you the time delta as `HH:MM:SS`. And if you want to calculate the number of minutes, you can use the `Hour()`, `Minute()` and `Second()` functions on that field:

``````=(Hour(D2) * 60) + Minute(D2) + (Second(D2) / 60)
``````

Of course, if there are leap-seconds, time zone changes, or if an event takes longer than 24 hours, you will still have to adjust the results manually.

### A warning

If one event stretches past midnight, say from 23:50 to 00:10, this will show up as a negative time!

In oder to have these events handled 'correctly', you can either put "24:10" or split the event into two.

## A Better way

Even though it's a bit harder to input data, the most reliable way to do this is to mark the beinning and end field as "Date Time" and the delta field as "Hours", which will look like this:

``````Beginning          End                  Delta
8/1/2013 0:00:00   8/2/2013 12:30:00    36:30:00
``````
-
This doesn't appear to work anymore. I think you need to choose Format > Number > Hours (vs. time). I get a very odd decimal number when I try to subtract simple hourly difference. – Elijah Lynn Jul 5 '13 at 17:27
@ElijahLynn this odd number are the number of days. Multiplying times 24 and 60 will give you the number of minutes, – Jacob Jan Tuinstra Jul 21 '13 at 12:36

I've done a lot of experimentation. This is the easiest way to calculate a time delta in Google Spreadsheets. Format the cell containing the formula like this:

Format > Number > More Formats > More date and time formats, delete "second" and `:`. Then, format the End time and Start time cells like this: `h:mm am/pm`.

Use the formula `=abs(end time - start time)`. This gives you an absolute value, so there won't be negative time values.

-

For a more robust solution, we uses a custom Function.

``````function toEpoch (indate) {
return indate.getTime();
}
``````

Then in the cell, writes:

``````=(toEpoch(C2)-toEpoch(B2)) / 60*1000
``````

Which convert the difference in Epoch milliseconds into minutes.

-

If you add the following formula in `D2`, then the minutes are calculated automatically:

## Formula

``````=ARRAYFORMULA(IF(ISBLANK(B2:B)=FALSE,((C2:C-B2:B)*24*60),""))
``````

## Explained

The difference between the times, as per decimal format, is expressed in days. Therefore multiplying times 24 time 60 will yield minutes

## Remark

There is one prerequisite: column D needs to be formated as 'normal'.

## Example

See example file I created: Delta Time

-

So much simpler: look at this B2: 23:00 C2: 1:37 D2: =C2-B2+(B2>C2)

Why it works, time is a fraction of a day, the comparison B2>C2 returns True (1) or False (0), if true 1 day (24 hours) is added. http://www.excelforum.com/excel-general/471757-calculating-time-difference-over-midnight.html

-

I agree that the time delta is expressed in days so to get back to say minutes you should multiply the difference by 1440, which is 24 x 60.

I had this problem today and thought I would mention the other simple method of getting the current time in a Google Docs spreadsheet is to enter `<CONTROL>:` in the cell. You can use this for both the Start and End Times cells.

If you need to enter the current date in a cell, then this is achieved by `<CONTROL>;`

HTH

-
Thanks for sharing, but it isn't an answer to the question. Read more tour that in our help center. Welcome to Web Applications !! – Jacob Jan Tuinstra Nov 6 '13 at 6:13