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: Using GEOMEAN with a Large List.

Using GEOMEAN with a Large List

by Allen Wyatt
(last updated April 11, 2015)


Ken wrote about a problem he was having with the GEOMEAN function. When he attempts to use the function on a large number of values (3,500 rows of data), he gets a #NUM error value returned.

The GEOMEAN function is used to return the geometric mean of a series of values. The GEOMEAN of n numbers is the n-th root of the product of the numbers. For example, if there are four values in a series (A through D), then the product of those numbers is A * B * C * D, and the GEOMEAN is the fourth root of that product.

The #NUM error would be return if any of three conditions were met: any of the values was equal to zero, any of the values was negative, or the limits of Excel were exceeded. It is likely that it is this last condition that Ken is running into, particularly if any of his 3,500 values are large.

Since GEOMEAN finds the product of the 3,500 numbers (multiplies them all by each other) and then takes the nth root, the product may easily be too large for Excel. The largest positive number in Excel is 9.99999999999999 * 10^307 (in scientific notation this is written as 9.99999999999999E+307). If the product gets larger than this number you will get a #NUM error for the function.

The solution is to use logs to do the calculation. This is easiest to understand when you look at a transformation of the GEOMEAN function:

GEOMEAN = (X1*X2*X3*...*Xn)^ (1/n)
ln(GEOMEAN) = ln((X1*X2*X3*...*Xn)^ (1/n))
ln(GEOMEAN) = (1/n) * ln(X1*X2*X3*...*Xn)
ln(GEOMEAN) = (1/n) * (ln(X1)+ln(X2)+ln(X3)+...+ln(Xn))
ln(GEOMEAN) = average(ln(X1)+ln(X2)+ln(X3)+...+ln(Xn))
GEOMEAN = exp(average(ln(X1)+ln(X2)+ln(X3)+...+ln(Xn)))

If you follow through the above, you see that GEOMEAN is equivalent to the exponent of the average of the logs of the values. You can calculate the desired result by using the following array formula instead of the GEOMEAN function:


This assumes that the desired values are in the range A1:A3500. Since it is an array formula, you must enter it into a cell by using Ctrl+Shift+Enter.

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (2580) 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: Using GEOMEAN with a Large List.

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. ...


An Automatic Two Spaces after a Period

Should you put two spaces after a sentence or just one? Ask different people and you will get different answers. To Word the ...

Discover More

Finding and Replacing with Subscripts

Want to use Find and Replace to change the formatting of a cell's contents? You would be out of luck; Excel won't let you do ...

Discover More

Updating Fields Automatically

You can place dynamic fields into many parts of your document. If your document contains a lot of fields, you might wonder ...

Discover More

Program Successfully in Excel! John Walkenbach's name is synonymous with excellence in deciphering complex technical topics. With this comprehensive guide, "Mr. Spreadsheet" shows how to maximize your Excel experience using professional spreadsheet application development tips from his own personal bookshelf. Check out Excel 2013 Power Programming with VBA today!

More ExcelTips (menu)

Using the FORECAST Function

Excel provides a handy worksheet function that allows you to forecast values based upon a set of known values. This function, ...

Discover More

An Average that Excludes Zero Values

Excel allows you to use functions and formulas to analyze your data. One way you can analyze your data is to use the AVERAGE ...

Discover More

Counting within Criteria

You can use the COUNTIF function to determine how many cells in a range fit your criteria. One criterion is easy; using ...

Discover More

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

View most recent newsletter.


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}] in your comment text. You’ll be prompted to upload your image when you submit the comment. 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 7 + 7?

2016-06-13 15:28:27


When I tried the function above with a small sample it did not generate a geometric mean value equivalent to the GEOMEAN function in Excel. I believe the problem is that--at least in my version of Excel (2007)-- AVERAGE(LN(A1:A3500)) is not the equivalent of AVERAGE(LN(A1)+LN(A2)+...+LN(3499)+LN(3500)). I therefore calculated the LNs in a new column and then used the formula above, minus the LN part; e.g., =EXP(AVERAGE(B1:B3500)) where the B column values equal LN of the A column values. This generates values that are equivalent to the GEOMEAN function.

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

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.