File Extension Library
Learn what a file extension means, its file type and what opens it

File extensions are the key to opening a file!

File extensions are the short suffixes that appear after the filename. They are used to indicate the file type. In their early use, file extensions were used to indicate the generic type of a file. For example, .txt was used for a text file, and file extension .gfx for a graphics file. However, over time, file extensions have become connected with certain programs or even versions of that program. A .doc file indicates a Microsoft Word document, while a .docx file extension means it was created using Word 2007 or a later version. Use the index below to locate file extensions and click on the links to learn about their file types and the programs that support them.

File Extension Index