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

SWF file extension

Shockwave Flash Movie

Video Files

CFM file extension

ColdFusion Markup File

Web Files

DXF file extension

Drawing Exchange Format File

CAD Files

7Z file extension

7-Zip Compressed File

Compressed Files

DLL file extension

Dynamic Link Library

System Files

ICS file extension

iCalendar File

Misc Files

MSI file extension

Windows Installer Package

Misc Files

VCXPROJ file extension

Visual C++ Project

Developer Files

TORRENT file extension

BitTorrent File

Misc Files

DRV file extension

Device Driver

System Files

TMP file extension

Temporary File

Backup Files

FLV file extension

Flash Video File

Video Files

DESKTHEMEPACK file extension

Windows 8 Desktop Theme Pack File

System Files

NES file extension

Nintendo (NES) ROM File

Game Files

SDF file extension

Standard Data File

Data Files