This is a list of file name extension or suffixes that indicate the format or usage of a file and a brief description of that format. We don't really show the file format itself here. In fact, many formats are proprietary and we couldn't show them to you. In some cases, we link to a definition of the file format or to related information.
In general, if you have the program that uses the file format, that program can be used to open or otherwise use the file. Some file formats (for example, the GIF file format used for Web page images) are standard formats that can be opened by any program that supports that standard format.

Many people have contributed to this list and we thank them! If you know of file name extensions that should be added to this list, please e-mail us and we'll add them.