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

CPL file extension

Windows Control Panel Item

System Files

DEB file extension

Debian Software Package

Compressed Files

DLL file extension

Dynamic Link Library

System Files

DMP file extension

Windows Memory Dump

System Files

HTM file extension

Hypertext Markup Language File

Web Files

IBOOKS file extension

Multi-Touch iBook

Data Files

M file extension

Objective-C Implementation File

Developer Files

PIF file extension

Program Information File

Executable Files

PL file extension

Perl Script

Developer Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

TEX file extension

LaTeX Source Document

Text Files

VB file extension

VBScript File

Executable Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

3G2 file extension

3GPP2 Multimedia File

Video Files