LOG Function in Excel: Syntax, Examples and Free Practice

By Rinkesh Shah, founder of Cellgrids.

LOG is an Excel Math & Trig function. Returns the logarithm of a number to a base you specify.

LOG syntax

=LOG(number, [base])

LOG is used in financial models and engineering-style calculations where precise numeric work is needed.

Open the live Excel-style spreadsheet and try LOG yourself. No Excel install or sign-up needed to start.

What does the LOG function do in Excel?

Returns the logarithm of a number to a base you specify.

What is the syntax of LOG in Excel?

The syntax is =LOG(number, [base]). number: A number to use in the calculation; base: The number system to convert into or out of (optional).

Where can I practice LOG online for free?

Open the free live spreadsheet on Cellgrids and try LOG yourself. No Excel install is needed and you can start without signing up.