The geometric mean is an average calculated by multiplying a set of numbers and taking the *n*th root, where *n* is the number of numbers.

For example, the geometric mean of 4, 8, 16 is:

(4 ×8 ×16)^{1/3}= 8

A common example of when the geometric mean is the correct choice average is when averaging growth rates, see compound annual growth rate.