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

EXE file extension

Windows Executable File

Executable Files

7Z file extension

7-Zip Compressed File

Compressed Files

GADGET file extension

Windows Gadget

Executable Files

YUV file extension

YUV Encoded Image File

Raster Image Files

PKG file extension

Mac OS X Installer Package

Compressed Files

XML file extension

XML File

Data Files

CPL file extension

Windows Control Panel Item

System Files

M4A file extension

MPEG-4 Audio File

Audio Files

TGA file extension

Targa Graphic

Raster Image Files

OTF file extension

OpenType Font

Font Files

DTD file extension

Document Type Definition File

Developer Files

WAV file extension

WAVE Audio File

Audio Files

JS file extension

JavaScript File

Web Files

HTML file extension

Hypertext Markup Language File

Web Files

PAGES file extension

Pages Document

Text Files