LOG function: Description, Usage, Syntax, Examples and Explanation

What is LOG function in Excel?

LOG function is one of the Math and Trig functions in Microsoft Excel that returns the logarithm of a number to the base you specify.

LOG(number, [base])

The LOG function syntax has the following arguments:

Number: The positive real number for which you want the logarithm.
Base(Optional): The base of the logarithm. If base is omitted, it is assumed to be 10.

Steps to follow:

1. Open a new Excel worksheet.

2. Copy data in the following table below and paste it in cell A1

Note: For formulas to show results, select them, press F2 key on your keyboard and then press Enter.

You can adjust the column widths to see all the data, if need be.

Formula	Description	Result
=LOG(10)	Logarithm of 10. Because the second argument (base) is omitted, it is assumed to be 10. The result, 1, is the power to which the base must be raised to equal 10.	1
=LOG(8, 2)	Logarithm of 8 with base 2. The result, 3, is the power to which the base must be raised to equal 8.	3
=LOG(86, 2.7182818)	Logarithm of 86 with base e (approximately 2.718). The result, 4.454, is the power to which the base must be raised to equal 86.	4.4543473