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

7Z file extension

7-Zip Compressed File

Compressed Files

TGA file extension

Targa Graphic

Raster Image Files

PPS file extension

PowerPoint Slide Show

Data Files

CGI file extension

Common Gateway Interface Script

Executable Files

GAM file extension

Saved Game File

Game Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

GADGET file extension

Windows Gadget

Executable Files

ZIPX file extension

Extended Zip File

Compressed Files

3DM file extension

Rhino 3D Model

3D Image Files

RSS file extension

Rich Site Summary

Web Files

SLN file extension

Visual Studio Solution File

Developer Files

WMV file extension

Windows Media Video File

Video Files

DLL file extension

Dynamic Link Library

System Files

FNT file extension

Windows Font File

Font Files

MPG file extension

MPEG Video File

Video Files