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

PPTX file extension

PowerPoint Open XML Presentation

Data Files

MPA file extension

MPEG-2 Audio File

Audio Files

TORRENT file extension

BitTorrent File

Misc Files

7Z file extension

7-Zip Compressed File

Compressed Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

LUA file extension

Lua Source File

Developer Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

CSS file extension

Cascading Style Sheet

Web Files

CBR file extension

Comic Book RAR Archive

Compressed Files

PPT file extension

PowerPoint Presentation

Data Files

MAX file extension

3ds Max Scene File

3D Image Files

PCT file extension

Picture File

Layout Files

WMA file extension

Windows Media Audio File

Audio Files

VOB file extension

DVD Video Object File

Video Files

ICO file extension

Icon File

System Files