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

ACCDB file extension

Access 2007 Database File

Database Files

AI file extension

Adobe Illustrator File

Vector Image Files

AZW file extension

Amazon Kindle eBook File

eBook Files

CUR file extension

Windows Cursor

System Files

DTD file extension

Document Type Definition File

Developer Files

GAM file extension

Saved Game File

Game Files

GBR file extension

Gerber File

Data Files

IBOOKS file extension

Multi-Touch iBook

Data Files

M file extension

Objective-C Implementation File

Developer Files

MSG file extension

Outlook Mail Message

Text Files

PDF file extension

Portable Document Format File

Layout Files

PHP file extension

PHP Source Code File

Web Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

SAV file extension

Saved Game

Game Files

WSF file extension

Windows Script File

Executable Files