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

APP file extension

Mac OS X Application

Executable Files

INI file extension

Windows Initialization File

Settings Files

3G2 file extension

3GPP2 Multimedia File

Video Files

EXE file extension

Windows Executable File

Executable Files

TXT file extension

Plain Text File

Text Files

GZ file extension

Gnu Zipped Archive

Compressed Files

BIN file extension

Binary Disc Image

Disk Image Files

CER file extension

Internet Security Certificate

Web Files

M3U file extension

Media Playlist File

Audio Files

H file extension

C/C++/Objective-C Header File

Developer Files

TARGZ file extension

Compressed Tarball File

Compressed Files

CS file extension

Visual C# Source Code File

Developer Files

7Z file extension

7-Zip Compressed File

Compressed Files

TGA file extension

Targa Graphic

Raster Image Files

VCXPROJ file extension

Visual C++ Project

Developer Files