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

VCXPROJ file extension

Visual C++ Project

Developer Files

ODT file extension

OpenDocument Text Document

Text Files

TOAST file extension

Toast Disc Image

Disk Image Files

DEB file extension

Debian Software Package

Compressed Files

DNG file extension

Digital Negative Image File

Camera Raw Files

INI file extension

Windows Initialization File

Settings Files

CS file extension

Visual C# Source Code File

Developer Files

MP3 file extension

MP3 Audio File

Audio Files

CSS file extension

Cascading Style Sheet

Web Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

7Z file extension

7-Zip Compressed File

Compressed Files

GIF file extension

Graphical Interchange Format File

Raster Image Files

TXT file extension

Plain Text File

Text Files

CFG file extension

Configuration File

Settings Files

ZIP file extension

Zipped File

Compressed Files