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

AIF file extension

Audio Interchange File Format

Audio Files

CER file extension

Internet Security Certificate

Web Files

CFG file extension

Configuration File

Settings Files

CUE file extension

Cue Sheet File

Disk Image Files

DEM file extension

Video Game Demo File

Game Files

GZ file extension

Gnu Zipped Archive

Compressed Files

MP3 file extension

MP3 Audio File

Audio Files

MPA file extension

MPEG-2 Audio File

Audio Files

PKG file extension

Mac OS X Installer Package

Compressed Files

PRF file extension

Outlook Profile File

Settings Files

PS file extension

PostScript File

Vector Image Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

TIF file extension

Tagged Image File

Raster Image Files

XCODEPROJ file extension

Xcode Project

Developer Files

3DS file extension

3D Studio Scene

3D Image Files