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

CAB file extension

Windows Cabinet File

System Files

RA file extension

Real Audio File

Audio Files

7Z file extension

7-Zip Compressed File

Compressed Files

DEM file extension

Video Game Demo File

Game Files

SLN file extension

Visual Studio Solution File

Developer Files

IFF file extension

Interchange File Format

Audio Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

SAV file extension

Saved Game

Game Files

CPL file extension

Windows Control Panel Item

System Files

PIF file extension

Program Information File

Executable Files

3DM file extension

Rhino 3D Model

3D Image Files

CPP file extension

C++ Source Code File

Developer Files

AIF file extension

Audio Interchange File Format

Audio Files

PL file extension

Perl Script

Developer Files

ICO file extension

Icon File

System Files