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

CRX file extension

Chrome Extension

Plugin Files

CSR file extension

Certificate Signing Request File

Web Files

GAM file extension

Saved Game File

Game Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

LNK file extension

Windows File Shortcut

System Files

MSI file extension

Windows Installer Package

Misc Files

ODT file extension

OpenDocument Text Document

Text Files

PAGES file extension

Pages Document

Text Files

PL file extension

Perl Script

Developer Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

SLN file extension

Visual Studio Solution File

Developer Files

VCF file extension

vCard File

Data Files

WSF file extension

Windows Script File

Executable Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

3GP file extension

3GPP Multimedia File

Video Files