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

DOCX file extension

Microsoft Word Open XML Document

Text Files

GIF file extension

Graphical Interchange Format File

Raster Image Files

GPX file extension

GPS Exchange File

GIS Files

GZ file extension

Gnu Zipped Archive

Compressed Files

H file extension

C/C++/Objective-C Header File

Developer Files

M3U file extension

Media Playlist File

Audio Files

M4V file extension

iTunes Video File

Video Files

MSI file extension

Windows Installer Package

Misc Files

OTF file extension

OpenType Font

Font Files

PART file extension

Partially Downloaded File

Misc Files

PRF file extension

Outlook Profile File

Settings Files

ROM file extension

N64 Game ROM File

Game Files

SH file extension

Bash Shell Script

Developer Files

SWF file extension

Shockwave Flash Movie

Video Files

XCODEPROJ file extension

Xcode Project

Developer Files