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

APP file extension

Mac OS X Application

Executable Files

BMP file extension

Bitmap Image File

Raster Image Files

CSS file extension

Cascading Style Sheet

Web Files

DAT file extension

Data File

Data Files

DEM file extension

Video Game Demo File

Game Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

GAM file extension

Saved Game File

Game Files

JS file extension

JavaScript File

Web Files

JSP file extension

Java Server Page

Web Files

MAX file extension

3ds Max Scene File

3D Image Files

PKG file extension

Mac OS X Installer Package

Compressed Files

TEX file extension

LaTeX Source Document

Text Files

ZIPX file extension

Extended Zip File

Compressed Files