# A to Z of Excel Functions: The LOG Function

18 October 2021

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

**The LOG function**

Logarithm is a term coined by Scottish mathematician John Napier (1550-1617), from the Greek word *logos* meaning "proportion, ratio or word" and *arithmos* meaning "number", which therefore roughly translates to "ratio-number".

For a given base, a logarithm states the power that the base must be raised to for a given number, *e.g.*

Therefore,

The **LOG **function returns the logarithm of a number to the base you specify. Its syntax is given by

**LOG(number, [base])**

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

**number:**this is required and represents the positive real number for which you wish to determine the logarithm**base:**this argument is optional and denotes the base of the logarithm. If it is omitted, the**base**is assumed to be 10.

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. *