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

AI file extension

Adobe Illustrator File

Vector Image Files

BMP file extension

Bitmap Image File

Raster Image Files

CRX file extension

Chrome Extension

Plugin Files

DMG file extension

Mac OS X Disk Image

Disk Image Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

EXE file extension

Windows Executable File

Executable Files

IBOOKS file extension

Multi-Touch iBook

Data Files

KMZ file extension

Google Earth Placemark File

GIS Files

LUA file extension

Lua Source File

Developer Files

PKG file extension

Mac OS X Installer Package

Compressed Files

RTF file extension

Rich Text Format File

Text Files

SLN file extension

Visual Studio Solution File

Developer Files

VCD file extension

Virtual CD

Disk Image Files

VCXPROJ file extension

Visual C++ Project

Developer Files

XCODEPROJ file extension

Xcode Project

Developer Files