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

AI file extension

Adobe Illustrator File

Vector Image Files

COM file extension

DOS Command File

Executable Files

CPL file extension

Windows Control Panel Item

System Files

FLV file extension

Flash Video File

Video 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

LUA file extension

Lua Source File

Developer Files

MPG file extension

MPEG Video File

Video Files

PL file extension

Perl Script

Developer Files

ROM file extension

N64 Game ROM File

Game Files

SLN file extension

Visual Studio Solution File

Developer Files

SYS file extension

Windows System File

System Files

VOB file extension

DVD Video Object File

Video Files

ZIP file extension

Zipped File

Compressed Files