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

AIF file extension

Audio Interchange File Format

Audio Files

ASX file extension

Microsoft ASF Redirector File

Video Files

CUE file extension

Cue Sheet File

Disk Image Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

INDD file extension

Adobe InDesign Document

Layout Files

JAR file extension

Java Archive File

Executable Files

M3U file extension

Media Playlist File

Audio Files

MDB file extension

Microsoft Access Database

Database Files

MPA file extension

MPEG-2 Audio File

Audio Files

MSI file extension

Windows Installer Package

Misc Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

RPM file extension

Red Hat Package Manager File

Compressed Files

SAV file extension

Saved Game

Game Files

SRT file extension

SubRip Subtitle File

Video Files

VCXPROJ file extension

Visual C++ Project

Developer Files