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

ICO file extension

Icon File

System Files

MOV file extension

Apple QuickTime Movie

Video Files

MDB file extension

Microsoft Access Database

Database Files

LUA file extension

Lua Source File

Developer Files

VCXPROJ file extension

Visual C++ Project

Developer Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

RTF file extension

Rich Text Format File

Text Files

CBR file extension

Comic Book RAR Archive

Compressed Files

7Z file extension

7-Zip Compressed File

Compressed Files

TAR file extension

Consolidated Unix File Archive

Data Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

CRX file extension

Chrome Extension

Plugin Files

INDD file extension

Adobe InDesign Document

Layout Files

ZIP file extension

Zipped File

Compressed Files