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

XML file extension

XML File

Data Files

CBR file extension

Comic Book RAR Archive

Compressed Files

FON file extension

Generic Font File

Font Files

IBOOKS file extension

Multi-Touch iBook

Data Files

BAT file extension

DOS Batch File

Executable Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

MOBI file extension

Mobipocket eBook

eBook Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

VB file extension

VBScript File

Executable Files

H file extension

C/C++/Objective-C Header File

Developer Files

TARGZ file extension

Compressed Tarball File

Compressed Files

XCODEPROJ file extension

Xcode Project

Developer Files

DDS file extension

DirectDraw Surface

Raster Image Files

7Z file extension

7-Zip Compressed File

Compressed Files

CER file extension

Internet Security Certificate

Web Files