Definition of the filename extension:

In Windows and some other operating systems, one or several letters (or numbers) at the end of a filename. Filename extensions indicate the type of information stored in the file. For example, in the filename EXAMPLE.TXT, the extension is TXT, which indicates that the file is a text file.

For example:

• exe means that a file is an executable program,
• zip means that a file is a ZIP compressed archive,
• htm is a HTML document,

and so on.

In Windows, if the extension is associated with an application, then you can just double-click on the file's icon to open it.

Note: Windows normally hides filename extensions!

More information about file extensions is available on Wikipedia.

Directions for use

• To search for a filename extension, type it into the search field at the top of this page, and click on the "Search" button. For example, to find information about the .mov extension, simply enter mov into the search field at the top and click on the button.
• At present, only exact can be entered for a search, the wildcard characters (like "*", "?", etc.) are not allowed!
• If you can't find an extension here, please come back later, our extension database is updated day by day!

If you know about an extension

If you find a new extension, a related link or useful information about extensions, then please click on the "Submit New" button at the top of the page and contact us.