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

BMP file extension

Bitmap Image File

Raster Image Files

CFG file extension

Configuration File

Settings Files

CS file extension

Visual C# Source Code File

Developer Files

DBF file extension

Database File

Database Files

DEB file extension

Debian Software Package

Compressed Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

GIF file extension

Graphical Interchange Format File

Raster Image Files

LNK file extension

Windows File Shortcut

System Files

MP4 file extension

MPEG-4 Video File

Video Files

NES file extension

Nintendo (NES) ROM File

Game Files

PAGES file extension

Pages Document

Text Files

PKG file extension

Mac OS X Installer Package

Compressed Files

SLN file extension

Visual Studio Solution File

Developer Files

VCXPROJ file extension

Visual C++ Project

Developer Files

WSF file extension

Windows Script File

Executable Files