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

CBR file extension

Comic Book RAR Archive

Compressed Files

DLL file extension

Dynamic Link Library

System Files

DMG file extension

Mac OS X Disk Image

Disk Image Files

DMP file extension

Windows Memory Dump

System 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

MSG file extension

Outlook Mail Message

Text Files

NES file extension

Nintendo (NES) ROM File

Game Files

PDF file extension

Portable Document Format File

Layout Files

PL file extension

Perl Script

Developer Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

VCF file extension

vCard File

Data Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

3G2 file extension

3GPP2 Multimedia File

Video Files