Excel Vba User Defined Functions

Refresh Excel VBA Function Results: A Complete Guide

When working with Excel, many users rely on the power of User-Defined Functions (UDFs) to perform specialized calculations. However, you might encounter a common issue: your UDFs do not re-evaluate automatically after changing related data in your spreadsheet. This can be frustrating, especially if you’ve spent time creating complex functions.

In this post, we’ll explore how to ensure that your Excel VBA functions refresh automatically whenever the data around them changes.

Understanding the Problem

You may have noticed that after making changes to your data, pressing F9 or even Shift + F9 does not seem to update the results generated by your user-defined functions. The only workaround you’ve found is to manually edit the cell containing the function and hit Enter, which is not ideal for streamlining your workflow.

Why Won’t My UDF Refresh Automatically?

User-defined functions in Excel, by default, do not automatically re-evaluate unless they are set to do so. This limitation means that even if your data changes, your UDF may return stale results unless it receives a direct command to recalculate.

The Solution: Making Your UDFs Volatile

To solve this issue, you can make your user-defined function volatile. Making a function volatile ensures that it recalculates every time Excel recalculates, which includes changes in other cells throughout the workbook.

How to Implement `Application.Volatile`

Here’s a straightforward step-by-step process for modifying your UDF to include the Application.Volatile method.

Open Your VBA Editor: Press ALT + F11 to open the VBA editor in Excel.
Locate Your Function: Find the relevant function in your project. For instance, if you have a function that doubles a number, you would look for it in your VBA module.
Insert Application.Volatile: At the beginning of your function, include the line Application.Volatile.

Here’s a simple example of how your function should look after modification:
```
Function doubleMe(d)
    Application.Volatile
    doubleMe = d * 2
End Function
```

Explanation of the Code

The Application.Volatile statement marks the function as volatile.
This makes the function execute every time Excel recalculates (when other cells are changed).
As a result, your output will always reflect the most current state of your data.

Setting Up Automatic Calculations in Excel

To ensure that your volatile function works effectively, be sure your Excel settings are configured for automatic calculations:

Go to the Formulas Tab: Click on the “Formulas” tab in the Ribbon.
Choose Calculation Options: In the Calculation group, make sure that “Automatic” is selected.

With this setup, your UDFs will update automatically based on changes, making your Excel experience more efficient and error-free.

Conclusion

In this guide, we addressed a common issue faced by Excel users regarding user-defined functions not refreshing as expected. By utilizing Application.Volatile, you can streamline your calculations and ensure your workbook stays updated without manual intervention.

Remember to keep your settings in check to enjoy the full benefits of your VBA functions. Happy calculating!