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

ASP file extension

Active Server Page

Web Files

BMP file extension

Bitmap Image File

Raster Image Files

CGI file extension

Common Gateway Interface Script

Executable Files

CLASS file extension

Java Class File

Developer Files

COM file extension

DOS Command File

Executable Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

EPUB file extension

Open eBook File

eBook Files

FON file extension

Generic Font File

Font Files

GPX file extension

GPS Exchange File

GIS Files

M3U file extension

Media Playlist File

Audio Files

ODT file extension

OpenDocument Text Document

Text Files

SWF file extension

Shockwave Flash Movie

Video Files

VCD file extension

Virtual CD

Disk Image Files

VCF file extension

vCard File

Data Files