Skip to content

How to Use Excel LOG Function?

LOG FunctionPin
LOG Function

Logarithms are the inverse of the exponential function. It is a mathematical expression used to find the power a base must raise to yield a given number. LOG in Excel is categorized as a Math/Trigonometry function. We all know Excel has plenty of features to perform mathematical operations. LOG is one of the built-in functions in Excel.

In this article, we will see the Excel LOG Function with its syntax, explanation, and examples. Get an official version of MS Excel from the following link:

LOG FunctionPin
LOG Function

Explanation of LOG Function

  • It is one of the built-in functions in Microsoft Excel.
  • This function returns the logarithm of a given number using the specified base.
  • If you don’t give the base value, it takes 10 as a base value by default.


  • Here, you will see the syntax of the LOG function.
  • To apply this function on your spreadsheet, you have to select a cell and enter the formula in the following format.
  • Once you enter the formula, just click on the Enter button to get the result.

=LOG(number, [base])

Argument Explanation:

  • Number – The input number to which you want the logarithm.
  • Base – It is optional. The base of the logarithm. If the base is omitted, it takes 10 by default.

1) If you give non-numeric values such as letters and special characters to the argument, it will return #VALUE! Error.
2) If the argument’s value is a negative integer, it returns #NUM! Error.


Here, we come up with some examples to know how to use the LOG function in the Excel spreadsheet.

  • In the below-given example, we have given the input number and its base value to find the LOG value using the Excel LOG function.
Input ValuesPin
Input Values
  • Then, you have to enter the formula in the cell as shown below to get the result.
Enter the formulaPin
Enter the formula
  • After entering the formula, you need to click the Enter button to get the output, as shown below. You can drag down the cell to fill the remaining cells.

Input that Causes Error

By seeing the below-given example, you will understand the input that causes errors in the spreadsheet. 

  • If any argument is a non-numeric value such as letters or special symbols, a LOG function will return #VALUE! Error.
  • If the argument’s value is a negative integer, it returns #NUM! Error.

From the above screenshots, you can clearly understand the usage of the LOG Function in Excel.


In the above article, you can understand how to use Excel LOG Function with its syntax, explanation, and examples. Share your feedback in the below comment section. To learn more about Excel functions, then visit our webpage

Video Tutorial

The below-given video will show you how to apply the Excel LOG function in the worksheet.

Read Also:


Leave a Reply

Your email address will not be published. Required fields are marked *

Share to...