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

AI file extension

Adobe Illustrator File

Vector Image Files

AZW file extension

Amazon Kindle eBook File

eBook Files

DMP file extension

Windows Memory Dump

System Files

GAM file extension

Saved Game File

Game Files

INI file extension

Windows Initialization File

Settings Files

LNK file extension

Windows File Shortcut

System Files

LUA file extension

Lua Source File

Developer Files

MDF file extension

Media Disc Image File

Disk Image Files

PIF file extension

Program Information File

Executable Files

PNG file extension

Portable Network Graphic

Raster Image Files

PPT file extension

PowerPoint Presentation

Data Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

VOB file extension

DVD Video Object File

Video Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

3DM file extension

Rhino 3D Model

3D Image Files