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

ASP file extension

Active Server Page

Web Files

CRX file extension

Chrome Extension

Plugin Files

GAM file extension

Saved Game File

Game Files

H file extension

C/C++/Objective-C Header File

Developer Files

IFF file extension

Interchange File Format

Audio Files

MSG file extension

Outlook Mail Message

Text Files

PART file extension

Partially Downloaded File

Misc Files

PCT file extension

Picture File

Layout Files

PY file extension

Python Script

Developer Files

RA file extension

Real Audio File

Audio Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

SAV file extension

Saved Game

Game Files

SRT file extension

SubRip Subtitle File

Video Files

SWF file extension

Shockwave Flash Movie

Video Files

TMP file extension

Temporary File

Backup Files