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

CFM file extension

ColdFusion Markup File

Web Files

COM file extension

DOS Command File

Executable Files

DBF file extension

Database File

Database Files

DMP file extension

Windows Memory Dump

System Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

EXE file extension

Windows Executable File

Executable Files

IBOOKS file extension

Multi-Touch iBook

Data Files

MAX file extension

3ds Max Scene File

3D Image Files

ODT file extension

OpenDocument Text Document

Text Files

PKG file extension

Mac OS X Installer Package

Compressed Files

RA file extension

Real Audio File

Audio Files

ROM file extension

N64 Game ROM File

Game Files

SRT file extension

SubRip Subtitle File

Video Files

WSF file extension

Windows Script File

Executable Files

ZIPX file extension

Extended Zip File

Compressed Files