Calculating an Average Time

Abhay has a worksheet that has a column indicating elapsed times, all in the format hh:mm. He would like to calculate an average of these times and wonders about the easiest way to do this.

In order to provide the "easy answer," it is necessary to make a couple of assumptions about your data. The first is that your data is really stored as times. Excel allows you to store dates and times in worksheet cells, and they are converted to serial numbers for ease in manipulation. For instance, when you enter a time as, say, 2:57 pm, Excel converts it to a date/time serial number during the entry process. You can see this by selecting the cell in which you just entered the time and looking at the Formula bar—it should show something like 2:57:00 PM.

If you insert an elapsed time that represents a number of hours greater than 24 (such as 32:15), Excel will still parse it correctly. It is only when you get to very large elapsed times that you can run into problems. If you do deal with very large elapsed times (more than, say, 10,000 hours), then you'll want to refer to this tip:

https://tips.net/T10594

The second assumption that needs to be made about your data is that the cells are formatted as actual elapsed times. You ensure this by following these steps:

1. Select all the cells containing your times. (If you want, you can select the entire column.)
2. Press Ctrl+Shift+F. Excel displays the Format Cells dialog box.
3. Make sure the Number tab is displayed.
4. Make sure that Time is selected in the Category list. (See Figure 1.)



Figure 1. The Number tab of the Format Cells dialog box.

5. Make sure that 37:30:55 is selected in the Type list. (This is the elapsed time format.)
6. Click on OK.

Now, with these two assumptions out of the way, it is very easy to calculate an average time. Let's say that your times are in cells A2:A324. You can use the following formula:

=AVERAGE(A2:A324)

That's right—you can use the AVERAGE function with times, and it will work wonderfully. The only thing you'll need to do is to make sure that the cell containing the formula is formatted using the elapsed time format. (Use the same steps outlined earlier in this tip.)

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (13865) applies to Microsoft Excel 2007, 2010, 2013, 2016, 2019, and 2021.