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

DEB file extension

Debian Software Package

Compressed Files

DESKTHEMEPACK file extension

Windows 8 Desktop Theme Pack File

System Files

DMG file extension

Mac OS X Disk Image

Disk Image Files

FLA file extension

Adobe Flash Animation

Developer Files

GIF file extension

Graphical Interchange Format File

Raster Image Files

JS file extension

JavaScript File

Web Files

M4V file extension

iTunes Video File

Video Files

MP3 file extension

MP3 Audio File

Audio Files

PCT file extension

Picture File

Layout Files

SH file extension

Bash Shell Script

Developer Files

TAR file extension

Consolidated Unix File Archive

Data Files

TARGZ file extension

Compressed Tarball File

Compressed Files

TIF file extension

Tagged Image File

Raster Image Files

TXT file extension

Plain Text File

Text Files

UUE file extension

Uuencoded File

Encoded Files