How to Calculate Logarithms in VBA (With Examples)

You can use the following syntax to calculate the log (base 10) of a value using VBA:

Function FindLog(number)
FindLog = Application.WorksheetFunction.Log(number)
End Function

And you can use the following syntax to calculate the natural log of a value using VBA:

Function FindNaturalLog(number)
FindNaturalLog = Log(number)
End Function

The following examples show how to use each function in practice.

Example 1: Calculate Log (Base 10) Using VBA

To calculate the log (base 10) of a value in Excel, we would use the LOG function as follows:

This tells us that the log of 5 is 0.69879.

To replicate this functionality in VBA, we can define the following function:

Function FindLog(number)
FindLog = Application.WorksheetFunction.Log(number)
End Function

We can then type this function into cell B2 to calculate the log of the value in cell B1:

This tells us that the log of 5 is 0.69879.

This matches the value calculated by the LOG function in Excel.

To calculate the natural log of a value in Excel, we would use the LN function as follows:

This tells us that the natural log of 5 is 1.609438.

To replicate this functionality in VBA, we can define the following function:

Function FindNaturalLog(number)
FindNaturalLog = Log(number)
End Function

We can then type this function into cell B2 to calculate the natural log of the value in cell B1:

natural log in VBA

This tells us that the log of 5 is 1.609438.

This matches the value calculated by the LN function in Excel.

The following tutorials explain how to perform other common tasks in VBA: