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

APK file extension

Android Package File

Executable Files

APP file extension

Mac OS X Application

Executable Files

CUE file extension

Cue Sheet File

Disk Image Files

DOC file extension

Microsoft Word Document

Text Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

GAM file extension

Saved Game File

Game Files

ICNS file extension

Mac OS X Icon Resource File

System Files

KEY file extension

Keynote Presentation

Data Files

M3U file extension

Media Playlist File

Audio Files

MP3 file extension

MP3 Audio File

Audio Files

PIF file extension

Program Information File

Executable Files

RTF file extension

Rich Text Format File

Text Files

TORRENT file extension

BitTorrent File

Misc Files

VCXPROJ file extension

Visual C++ Project

Developer Files

WPD file extension

WordPerfect Document

Text Files