Computer file extensions and file help

Updated: 06/30/2019 by Computer Hope
The .txt file extension.

A computer file extension is commonly a three-character addition that follows the name of a file. A few of the more common file extensions include EXE, DOC or DOCX, XLS, TXT, PDF, and MP3.


For a complete list of file extensions broken down to categories, see: What are the most common file types and file extensions?

Complete list of file extensions

Below is an alphabetical list of links to thousands of file extensions and brief descriptions currently listed on Computer Hope. For the file extension you are looking for, click the first letter of the file extension. For example, if you're looking for information about an .EXE file, click "E."

Computer file and file extension help