The Excel LOG10 Function

Related Function:
LOG Function

Base 10 Logarithm

The Logarithm of a number, to a given base, is the power to which the base must be raised to give that number.

The Base 10 Logarithm of a number, (also known as the Common Logarithm and written as Log10(x) ), is the logarithm to the base 10.


If   10x = y   Then   Log10(y) = x

Basic Description

The Excel LOG10 function calculates the base 10 logarithm of a given number.

The format of the function is :

LOG10( number )

where the number argument is a positive real number that you want to calculate the base 10 logarithm of.

Log10 Function Examples

In the examples below, the Excel Log10 function is used to calculate the base 10 logarithms of different numbers.

1=LOG10( 100 )
2=LOG10( 1000 )
3=LOG10( 0.001 )
4=LOG10( 25 )
12  102 = 100; Therefore, Log10(100) = 2
23  103 = 1000; Therefore, Log10(1000) = 3
3-3  10-3 = 0.001; Therefore, Log10(0.001) = -3
41.397940009  101.397940009 = 25; Therefore, Log10(25) = 1.397940009

Further examples of the Excel Log10 function can be found on the Microsoft Office website.

Common Errors

If you get an error from your Excel Log10 function, use the following table to diagnose the likely cause :

Common Errors
#NUM!-Produced if the supplied number argument is negative or zero
#NAME?-Produced if the supplied number argument is not a numeric value