LOG function

The Excel LOG function is used to calculate the logarithm of a number to a specified base. It helps you find the exponent to which the base must be raised to get the given number.


LOG(number, [base])


numberThe positive number for which you want to calculate the logarithm.
[base](Optional) The base for the logarithm. If omitted, the default base is 10.

How to Use

The LOG function is straightforward to use. You provide a number and, optionally, the base for the logarithm. Here are some examples to illustrate its usage:

This formula calculates the logarithm of 100 with the default base of 10, which is 2 (because 10^2 = 100).

This formula finds the logarithm of 8 with a base of 2, which is 3 (because 2^3 = 8).

Here, we calculate the logarithm of 1000 with a base of 10, which is 3 (because 10^3 = 1000).

The LOG function is useful for various applications, such as scientific calculations and financial modeling. It helps you solve problems where exponential growth or decay is involved, like compound interest or population growth.

Tomasz Decker is an Excel specialist, skilled in data analysis and financial modeling.