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

APP file extension

Mac OS X Application

Executable Files

CBR file extension

Comic Book RAR Archive

Compressed Files

CPP file extension

C++ Source Code File

Developer Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

FON file extension

Generic Font File

Font Files

GAM file extension

Saved Game File

Game Files

IFF file extension

Interchange File Format

Audio Files

INDD file extension

Adobe InDesign Document

Layout Files

KML file extension

Keyhole Markup Language File

GIS Files

MPG file extension

MPEG Video File

Video Files

PPS file extension

PowerPoint Slide Show

Data Files

VCF file extension

vCard File

Data Files

WMA file extension

Windows Media Audio File

Audio Files

WMV file extension

Windows Media Video File

Video Files

3GP file extension

3GPP Multimedia File

Video Files