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

C file extension

C/C++ Source Code File

Developer Files

EXE file extension

Windows Executable File

Executable Files

FLA file extension

Adobe Flash Animation

Developer Files

KML file extension

Keyhole Markup Language File

GIS Files

M4A file extension

MPEG-4 Audio File

Audio Files

MID file extension

MIDI File

Audio Files

MSI file extension

Windows Installer Package

Misc Files

RA file extension

Real Audio File

Audio Files

RTF file extension

Rich Text Format File

Text Files

SDF file extension

Standard Data File

Data Files

SLN file extension

Visual Studio Solution File

Developer Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

TORRENT file extension

BitTorrent File

Misc Files

WMV file extension

Windows Media Video File

Video Files

3GP file extension

3GPP Multimedia File

Video Files