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

AIF file extension

Audio Interchange File Format

Audio Files

ASP file extension

Active Server Page

Web Files

CBR file extension

Comic Book RAR Archive

Compressed Files

CFM file extension

ColdFusion Markup File

Web Files

DBF file extension

Database File

Database Files

DOC file extension

Microsoft Word Document

Text Files

DTD file extension

Document Type Definition File

Developer Files

LUA file extension

Lua Source File

Developer Files

MOBI file extension

Mobipocket eBook

eBook Files

MOV file extension

Apple QuickTime Movie

Video Files

MPA file extension

MPEG-2 Audio File

Audio Files

PHP file extension

PHP Source Code File

Web Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

SH file extension

Bash Shell Script

Developer Files

WMV file extension

Windows Media Video File

Video Files