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

APP file extension

Mac OS X Application

Executable Files

ASP file extension

Active Server Page

Web Files

CSV file extension

Comma Separated Values File

Data Files

DEM file extension

Video Game Demo File

Game Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

DXF file extension

Drawing Exchange Format File

CAD Files

LNK file extension

Windows File Shortcut

System Files

ODT file extension

OpenDocument Text Document

Text Files

PAGES file extension

Pages Document

Text Files

PCT file extension

Picture File

Layout Files

PPS file extension

PowerPoint Slide Show

Data Files

ROM file extension

N64 Game ROM File

Game Files

VCD file extension

Virtual CD

Disk Image Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

XML file extension

XML File

Data Files