How to Open UDF Files

Updated April 17, 2017

You can open User Defined Function (UDF) files with Microsoft Excel. Microsoft Excel User Defined Functions are also known as custom functions. Users create UDF files using Microsoft Excel's workbooks. UDFs allow users to create math functions, array formulas, text manipulation and diagnostics. You can also use Excel spreadsheets to create UDF files.

Click the "Start" button or Windows logo in the left corner of the screen to open the Start menu.

Click "All Programs" and open the "Microsoft Office" folder.

Open "Microsoft Excel." Click "File" on the menu bar.

Click "Open." Locate the UDF file you wish to open. Highlight the file and click "Open."

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About the Author

A family therapist and graduate of the University of Louisville, Tyran DeWalt has written relationship and holistic self-care practice advice for close to a decade. DeWalt relishes in being able to combine his zeal for writing and his commitment to assisting people manage everyday life challenges.