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

BMP file extension

Bitmap Image File

Raster Image Files

DEM file extension

Video Game Demo File

Game Files

DMG file extension

Mac OS X Disk Image

Disk Image Files

FNT file extension

Windows Font File

Font Files

HTML file extension

Hypertext Markup Language File

Web Files

MP4 file extension

MPEG-4 Video File

Video Files

NES file extension

Nintendo (NES) ROM File

Game Files

ODT file extension

OpenDocument Text Document

Text Files

RA file extension

Real Audio File

Audio Files

ROM file extension

N64 Game ROM File

Game Files

SH file extension

Bash Shell Script

Developer Files

TIFF file extension

Tagged Image File Format

Raster Image Files

TORRENT file extension

BitTorrent File

Misc Files

VCXPROJ file extension

Visual C++ Project

Developer Files

3G2 file extension

3GPP2 Multimedia File

Video Files