Excel: Log Function

In Excel, the Log function returns the logarithm of a number to a specified base.

The syntax for the Log function is:

Log( number, base )

number is a numeric value that must be greater than 0.

base is optional. This is the base to use to calculate the logarithm of a number. If this parameter is omitted, the Log function will use a base of 10.

Applies To:

Excel 2007, Excel 2003, Excel XP, Excel 2000

For example:

Let's take a look at an example:

Based on the Excel spreadsheet above:

=Log(A1) would return 1.301029996

=Log(A1, 10) would return 1.301029996

=Log(A1, A2) would return 0.930676558

=Log(A2, 5.1) would return 1.975690972

=Log(200, 3) would return 4.822736302

VBA Code

The Log function can also be used in VBA code. However in VBA, the Log function returns the natural logarithm of a number.

The syntax for the Log function in VBA is:

Log( number )

number is a numeric value that must be greater than 0.

For example:

Dim LResult As Double

LResult = Log(20)

In this example, the variable called LResult would now contain the value 2.995732274.