Creating a User Defined Function (UDF) in Excel using Visual Basic for Applications (VBA) allows you to perform custom calculations beyond the capabilities of built-in Excel functions.
Step 1: Open the Visual Basic Editor
- Open Excel and press
Alt + F11to open the Visual Basic for Applications (VBA) editor.
Step 2: Insert a New Module
- In the VBA editor, right-click on any of the objects in the Project Explorer window (usually on the left side).
- Choose
Insert>Module. This creates a new module for your code.
Step 3: Define the Function
- In the newly created module, type the
Functionstatement to define your UDF. The basic syntax is as follows:
Function MyFunctionName(Param1 As DataType, Param2 As DataType, …) As ReturnType
‘ Your code here
End Function
- Replace
MyFunctionNamewith the name of your function,Param1,Param2, etc., with your parameters,DataTypewith the type of your parameters (e.g.,Integer,String), andReturnTypewith the type of value your function will return.
Step 4: Write Your Function’s Code
- Inside the function, write the VBA code that performs the calculation or operation you want.
Step 5: Save Your Work
- Press
Ctrl + Sto save your work. Ensure your Excel workbook is saved as a macro-enabled workbook (.xlsm).
Example: Creating a Simple UDF to Add Two Numbers
Let’s create a UDF named AddNumbers that takes two numbers as input and returns their sum.
- Follow Steps 1 and 2 to open the VBA editor and insert a new module.
2. Define the function as follows:
Function AddNumbers(Number1 As Double, Number2 As Double) As Double
AddNumbers = Number1 + Number2
End Function
Save your work and return to Excel.
How to Use Your UDF in Excel
- In Excel, you can now use your UDF like any other function. For example, to use the
AddNumbersfunction, enter=AddNumbers(5, 3)in a cell, and it will return8.
Creating UDFs in Excel can significantly enhance your productivity by automating repetitive calculations and extending Excel’s functionality to meet your specific needs.
Creating UDFs in 
