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

ASX file extension

Microsoft ASF Redirector File

Video Files

DESKTHEMEPACK file extension

Windows 8 Desktop Theme Pack File

System Files

GZ file extension

Gnu Zipped Archive

Compressed Files

INI file extension

Windows Initialization File

Settings Files

JS file extension

JavaScript File

Web Files

NES file extension

Nintendo (NES) ROM File

Game Files

PL file extension

Perl Script

Developer Files

RTF file extension

Rich Text Format File

Text Files

SAV file extension

Saved Game

Game Files

SLN file extension

Visual Studio Solution File

Developer Files

TOAST file extension

Toast Disc Image

Disk Image Files

WAV file extension

WAVE Audio File

Audio Files

WSF file extension

Windows Script File

Executable Files

3DM file extension

Rhino 3D Model

3D Image Files