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

CRX file extension

Chrome Extension

Plugin Files

DAT file extension

Data File

Data Files

DB file extension

Database File

Database Files

GBR file extension

Gerber File

Data Files

IBOOKS file extension

Multi-Touch iBook

Data Files

KML file extension

Keyhole Markup Language File

GIS Files

M4A file extension

MPEG-4 Audio File

Audio Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

MPA file extension

MPEG-2 Audio File

Audio Files

MSG file extension

Outlook Mail Message

Text Files

MSI file extension

Windows Installer Package

Misc Files

RSS file extension

Rich Site Summary

Web Files

SWF file extension

Shockwave Flash Movie

Video Files

WMA file extension

Windows Media Audio File

Audio Files

WSF file extension

Windows Script File

Executable Files