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

AVI file extension

Audio Video Interleave File

Video Files

DOC file extension

Microsoft Word Document

Text Files

GAM file extension

Saved Game File

Game Files

GPX file extension

GPS Exchange File

GIS Files

IFF file extension

Interchange File Format

Audio Files

M4V file extension

iTunes Video File

Video Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

PRF file extension

Outlook Profile File

Settings Files

SITX file extension

StuffIt X Archive

Compressed Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

TARGZ file extension

Compressed Tarball File

Compressed Files

TORRENT file extension

BitTorrent File

Misc Files

TTF file extension

TrueType Font

Font Files

WMA file extension

Windows Media Audio File

Audio Files

3GP file extension

3GPP Multimedia File

Video Files