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

DAT file extension

Data File

Data Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

DTD file extension

Document Type Definition File

Developer Files

PRF file extension

Outlook Profile File

Settings Files

7Z file extension

7-Zip Compressed File

Compressed Files

LUA file extension

Lua Source File

Developer Files

SWF file extension

Shockwave Flash Movie

Video Files

FLA file extension

Adobe Flash Animation

Developer Files

WMA file extension

Windows Media Audio File

Audio Files

DMP file extension

Windows Memory Dump

System Files

PPS file extension

PowerPoint Slide Show

Data Files

TXT file extension

Plain Text File

Text Files

TTF file extension

TrueType Font

Font Files

MP3 file extension

MP3 Audio File

Audio Files

VCF file extension

vCard File

Data Files