# A to Z of Excel Functions: the GEOMEAN Function

13 February 2020

*Welcome back to our regular A to Z of Excel Functions blog. Today we look at the GEOMEAN function. *

**The GEOMEAN function**

In mathematics, the geometric mean is a mean or average, which indicates the central tendency or typical value of a set of numbers by using the product of their values (as opposed to the arithmetic mean which uses their sum). The geometric mean is defined as the **n**th root of the product of **n** numbers, *i.e.* for a set of numbers **x _{1}**,

**x**, ...,

_{2}**x**, the geometric mean is defined as

_{n}In two dimensions, it is the equivalent of finding the equivalent square with the same area as the rectangle given by the two dimensions cited:

In three dimensions, it is the equivalent of finding the equivalent cube with the same volume as the given hexahedron with the three dimensions cited:

The idea continues in **n **dimensions.

The Excel function **GEOMEAN **returns the geometric mean of an array or range of positive data. For example, you can use **GEOMEAN** to calculate average growth rate given compound interest with variable rates. It has the following syntax:

**GEOMEAN(number1, [number2], ...)**

The **GEOMEAN** function has the following arguments:

**number1**,**number2**, ... where**number1**is required, and subsequent numbers are optional. There can be between one (1) and 255 numbers. You can also use a single array or a reference to an array instead of arguments separated by commas.

It should be further noted that:

- arguments can either be numbers or names, arrays, or references that contain numbers
- logical values and text representations of numbers that you type directly into the list of arguments are counted
- of an array or reference argument contains text, logical values or empty cells, those values are ignored; however, cells with the value zero are included
- arguments that are error values or text that cannot be translated into numbers cause errors
- if any data point ≤ 0,
**GEOMEAN**returns the*#NUM!*error value - the equation for the geometric mean is:

Please see my example below:

*We’ll continue our A to Z of Excel Functions soon. Keep checking back – there’s a new blog post every business day.*

*A full page of the function articles can be found here. *