File extensions – definition and basic information


File extensions are the integral parts of the files that are on each computer. Often, when working on a computer, we encounter a wide range of files, such as docx, ppt, part, mp3 or rmvb. We realize that they are there – but we often do not know what they are for on our computer.

File extension, also known as the filename extension is a suffix added to the name of a computer file, usually consisting of a number of characters placed after the last dot in the filename, which gives us information about its coding. In other words a file extension is a file format. It allows the operating system (e.g. Windows) to recognize what program it should try to open the file.

In the table below you will find a random selection of popular file extensions.


File extension The full name of the file Category

WMA file extension

Windows Media Audio File

Audio Files

MP4 file extension

MPEG-4 Video File

Video Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

XCODEPROJ file extension

Xcode Project

Developer Files

DOC# file extension

Microsoft Word Document

Text Files

BIN file extension

Binary Disc Image

Disk Image Files

ODT file extension

OpenDocument Text Document

Text Files

TORRENT file extension

BitTorrent File

Misc Files

DOC file extension

Microsoft Word Document

Text Files

7Z file extension

7-Zip Compressed File

Compressed Files

PHP file extension

PHP Source Code File

Web Files

HTM file extension

Hypertext Markup Language File

Web Files

MP3 file extension

MP3 Audio File

Audio Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

CGI file extension

Common Gateway Interface Script

Executable Files