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

CPL file extension

Windows Control Panel Item

System Files

DB file extension

Database File

Database Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

FLV file extension

Flash Video File

Video Files

FNT file extension

Windows Font File

Font Files

KMZ file extension

Google Earth Placemark File

GIS Files

M4V file extension

iTunes Video File

Video Files

PART file extension

Partially Downloaded File

Misc Files

PKG file extension

Mac OS X Installer Package

Compressed Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

RTF file extension

Rich Text Format File

Text Files

TORRENT file extension

BitTorrent File

Misc Files

VCXPROJ file extension

Visual C++ Project

Developer Files

3DS file extension

3D Studio Scene

3D Image Files