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

ASF file extension

Advanced Systems Format File

Video Files

CBR file extension

Comic Book RAR Archive

Compressed Files

CPL file extension

Windows Control Panel Item

System Files

DEM file extension

Video Game Demo File

Game Files

DNG file extension

Digital Negative Image File

Camera Raw Files

FON file extension

Generic Font File

Font Files

GBR file extension

Gerber File

Data Files

JPG file extension

JPEG Image

Raster Image Files

KEY file extension

Keynote Presentation

Data Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

KMZ file extension

Google Earth Placemark File

GIS Files

PPS file extension

PowerPoint Slide Show

Data Files

SH file extension

Bash Shell Script

Developer Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

3DM file extension

Rhino 3D Model

3D Image Files