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

CBR file extension

Comic Book RAR Archive

Compressed Files

7Z file extension

7-Zip Compressed File

Compressed Files

JSP file extension

Java Server Page

Web Files

LUA file extension

Lua Source File

Developer Files

INDD file extension

Adobe InDesign Document

Layout Files

AIF file extension

Audio Interchange File Format

Audio Files

ICS file extension

iCalendar File

Misc Files

IFF file extension

Interchange File Format

Audio Files

DRV file extension

Device Driver

System Files

PHP file extension

PHP Source Code File

Web Files

GADGET file extension

Windows Gadget

Executable Files

DEM file extension

Video Game Demo File

Game Files

GZ file extension

Gnu Zipped Archive

Compressed Files

KMZ file extension

Google Earth Placemark File

GIS Files

INI file extension

Windows Initialization File

Settings Files