File Extension

A file extension is a suffix to the name of a computer file applied to indicate the encoding convention (file format) of its contents. A file extension is usually three or more characters at the end of the computer file name, after the period (dot). File extensions are useful for computer operating systems, like Microsoft Windows or Apple MAC OS X, basicaly telling them what kind of data the file contains and with which application it is associated.

Shortly, disk files have to be identified so the operating system can address them. These filenames have specific rules.

The basic form of a filename is: rootname.ext

For various security reasons, you should first make certain that your computer always shows file extensions.

If you encounter a file in your computer with an unknown extension, welcome to our site, here's where you want to be!

We have created a huge database, which is growing day by day, and put together a searchable list containing thousands of file extensions. A large number of file type entries have detailed descriptions, including their current use and a list of applications associated with them and which can handle the unknown file type you were searching for. Simply use the search box at the top-right corner of each page to check our database for a specific file extension. You may also browse our database in alphabetical order using the navigation menu at the top.