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

CPP file extension

C++ Source Code File

Developer Files

CUE file extension

Cue Sheet File

Disk Image Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

DRV file extension

Device Driver

System Files

INI file extension

Windows Initialization File

Settings Files

JS file extension

JavaScript File

Web Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

PHP file extension

PHP Source Code File

Web Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

SAV file extension

Saved Game

Game Files

SRT file extension

SubRip Subtitle File

Video Files

SWF file extension

Shockwave Flash Movie

Video Files

TIF file extension

Tagged Image File

Raster Image Files

YUV file extension

YUV Encoded Image File

Raster Image Files