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

PL file extension

Perl Script

Developer Files

3G2 file extension

3GPP2 Multimedia File

Video Files

WPD file extension

WordPerfect Document

Text Files

FNT file extension

Windows Font File

Font Files

SAV file extension

Saved Game

Game Files

OTF file extension

OpenType Font

Font Files

BAT file extension

DOS Batch File

Executable Files

MPA file extension

MPEG-2 Audio File

Audio Files

MP3 file extension

MP3 Audio File

Audio Files

CRX file extension

Chrome Extension

Plugin Files

M3U file extension

Media Playlist File

Audio Files

7Z file extension

7-Zip Compressed File

Compressed Files

SYS file extension

Windows System File

System Files

CS file extension

Visual C# Source Code File

Developer Files

SWF file extension

Shockwave Flash Movie

Video Files