Please Note: This article is written for users of the following Microsoft Excel versions: 97, 2000, 2002, and 2003. If you are using a later version (Excel 2007 or later), this tip may not work for you. For a version of this tip written specifically for later versions of Excel, click here: Averaging the Last Numbers in a Column.

Averaging the Last Numbers in a Column

Written by Allen Wyatt (last updated May 1, 2020)
This tip applies to Excel 97, 2000, 2002, and 2003


1

Emma has a list of numbers in a worksheet (let's say in column A) that are added to on a weekly basis. She needs to calculate the average of the last 12 numbers in the column. She wonders how she can do this and have the average always reflect the last 12 numbers, even when she keeps adding numbers each week.

Assuming that there are no gaps in your range of numbers, you can calculate the average of the last 12 numbers with this formula:

=AVERAGE(OFFSET(A1,COUNTA(A:A)-12,0,12,1))

This formula should, of course, be placed in some cell that is not in column A. It uses the COUNTA function to figure out how many cells contain something in column A. If there are 100 cells in use in column A, this means that you end up with a formula being evaluated in this way:

=AVERAGE(OFFSET(A1,100-12,0,12,1))

Of course, 100 minus 12 is 88, and this number is used as an offset from the starting cell (A2) to say that the range to be averaged should start at A89 and extend down 12 cells. That means that the average ends up being for the range A89:A100. As more numbers are added at the bottom of column A, the formula always reflects the last 12 numbers.

The formula will return an error if column A has fewer than 12 rows worth of data in it. To accommodate that possibility, you may want to alter the formula just a bit:

=AVERAGE(OFFSET(A1,COUNTA(A:A)-MIN(COUNTA(A:A),12),0,MIN(COUNTA(A:A),12),1))

Instead of using a hard-and-fast value of 12 rows, the MIN function (in two places) returns the minimum of either the actual number of rows or 12. So, if your worksheet only has numbers in cells A1:A5, the MIN function would ensure that the formula only averaged those 5 values.

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (10277) applies to Microsoft Excel 97, 2000, 2002, and 2003. You can find a version of this tip for the ribbon interface of Excel (Excel 2007 and later) here: Averaging the Last Numbers in a Column.

Author Bio

Allen Wyatt

With more than 50 non-fiction books and numerous magazine articles to his credit, Allen Wyatt is an internationally recognized author. He is president of Sharon Parq Associates, a computer and publishing services company. ...

MORE FROM ALLEN

Disabling a Function Key

Function keys are used to perform common tasks in Excel. If you want to disable one of the function keys, it's rather ...

Discover More

Backing Up Label Layouts

Once you create a custom label layout it is a good idea to backup the layout on a different hard drive in the event of a ...

Discover More

Drop-Down List Font Sizes

Excel has several features that cannot be customized. The font size in the drop-down lists is one of them. If you need ...

Discover More

Create Custom Apps with VBA! Discover how to extend the capabilities of Office 365 applications with VBA programming. Written in clear terms and understandable language, the book includes systematic tutorials and contains both intermediate and advanced content for experienced VB developers. Designed to be comprehensive, the book addresses not just one Office application, but the entire Office suite. Check out Mastering VBA for Microsoft Office 365 today!

More ExcelTips (menu)

Condensing Sequential Values to a Single Row

If you have a bunch of ZIP Codes or part numbers in a list, you may want to "condense" the list so that sequential series ...

Discover More

Counting Asterisks

For some operations and functions, Excel allows you to use wild card characters. One such character is an asterisk. What ...

Discover More

Finding the Nth Occurrence of a Character

The FIND and SEARCH functions are great for finding the initial occurrence of a character in a text string, but what if ...

Discover More
Subscribe

FREE SERVICE: Get tips like this every week in ExcelTips, a free productivity newsletter. Enter your address and click "Subscribe."

View most recent newsletter.

Comments

If you would like to add an image to your comment (not an avatar, but an image to help in making the point of your comment), include the characters [{fig}] (all 7 characters, in the sequence shown) in your comment text. You’ll be prompted to upload your image when you submit the comment. Maximum image size is 6Mpixels. Images larger than 600px wide or 1000px tall will be reduced. Up to three images may be included in a comment. All images are subject to review. Commenting privileges may be curtailed if inappropriate images are posted.

What is five minus 1?

2015-11-01 02:14:19

Thomas Papavasiliou

Mind that column A should not contain any empty cells that precedes the last twelve, as the COUNTA function returns the count of non empty cells in the reference.


This Site

Got a version of Excel that uses the menu interface (Excel 97, Excel 2000, Excel 2002, or Excel 2003)? This site is for you! If you use a later version of Excel, visit our ExcelTips site focusing on the ribbon interface.

Newest Tips
Subscribe

FREE SERVICE: Get tips like this every week in ExcelTips, a free productivity newsletter. Enter your address and click "Subscribe."

(Your e-mail address is not shared with anyone, ever.)

View the most recent newsletter.