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

MSI file extension

Windows Installer Package

Misc Files

TEX file extension

LaTeX Source Document

Text Files

GZ file extension

Gnu Zipped Archive

Compressed Files

CSS file extension

Cascading Style Sheet

Web Files

7Z file extension

7-Zip Compressed File

Compressed Files

JAVA file extension

Java Source Code File

Developer Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

TORRENT file extension

BitTorrent File

Misc Files

CS file extension

Visual C# Source Code File

Developer Files

PS file extension

PostScript File

Vector Image Files

PHP file extension

PHP Source Code File

Web Files

AI file extension

Adobe Illustrator File

Vector Image Files

DEB file extension

Debian Software Package

Compressed Files

TARGZ file extension

Compressed Tarball File

Compressed Files

SAV file extension

Saved Game

Game Files