Using the Excel LOG Function


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.


=LOG (number, [base])

Syntax Breakdown

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

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