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

ASP file extension

Active Server Page

Web Files

BAT file extension

DOS Batch File

Executable Files

CER file extension

Internet Security Certificate

Web Files

CRX file extension

Chrome Extension

Plugin Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

HTML file extension

Hypertext Markup Language File

Web Files

IFF file extension

Interchange File Format

Audio Files

KML file extension

Keyhole Markup Language File

GIS Files

KMZ file extension

Google Earth Placemark File

GIS Files

PCT file extension

Picture File

Layout Files

SH file extension

Bash Shell Script

Developer Files

SLN file extension

Visual Studio Solution File

Developer Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

TARGZ file extension

Compressed Tarball File

Compressed Files

TEX file extension

LaTeX Source Document

Text Files