LOG

Using the Excel LOG Function

Summary

Excel's LOG function returns the logarithm of a number with a user specified base. The LOG10 function can be used to find the base 10 logarithm of a given positive number.

Syntax

=LOG (number, [base])

Syntax Breakdown

number
The number argument is required in the LOG function and is the positive real number of which you want to find the logarithm.

[base]
The base argument is optional. If the field is left blank it will default to 10.


Usage Notes

The LOG function allows you to find the logarithm of a number with a specified base.

Excel LN Example

LOG Errors
If the number argument is either zero (0) or negative, the function will return the #NUM! error. If number is non-numeric, then the #VALUE! error is returned.

Excel LOG Errors