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

AIF file extension

Audio Interchange File Format

Audio Files

BMP file extension

Bitmap Image File

Raster Image Files

CFG file extension

Configuration File

Settings Files

DESKTHEMEPACK file extension

Windows 8 Desktop Theme Pack File

System Files

DMG file extension

Mac OS X Disk Image

Disk Image Files

DOC file extension

Microsoft Word Document

Text Files

GIF file extension

Graphical Interchange Format File

Raster Image Files

JS file extension

JavaScript File

Web Files

MP4 file extension

MPEG-4 Video File

Video Files

PPT file extension

PowerPoint Presentation

Data Files

RM file extension

Real Media File

Video Files

SQL file extension

Structured Query Language Data File

Database Files

TEX file extension

LaTeX Source Document

Text Files

TXT file extension

Plain Text File

Text Files

VCXPROJ file extension

Visual C++ Project

Developer Files