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

INI file extension

Windows Initialization File

Settings Files

BIN file extension

Binary Disc Image

Disk Image Files

TARGZ file extension

Compressed Tarball File

Compressed Files

CPL file extension

Windows Control Panel Item

System Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

DEB file extension

Debian Software Package

Compressed Files

KML file extension

Keyhole Markup Language File

GIS Files

TAR file extension

Consolidated Unix File Archive

Data Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

7Z file extension

7-Zip Compressed File

Compressed Files

TTF file extension

TrueType Font

Font Files

MPG file extension

MPEG Video File

Video Files

DTD file extension

Document Type Definition File

Developer Files

VCF file extension

vCard File

Data Files

NES file extension

Nintendo (NES) ROM File

Game Files