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

BMP file extension

Bitmap Image File

Raster Image Files

CAB file extension

Windows Cabinet File

System Files

CPP file extension

C++ Source Code File

Developer Files

GPX file extension

GPS Exchange File

GIS Files

ICO file extension

Icon File

System Files

JAR file extension

Java Archive File

Executable Files

MOV file extension

Apple QuickTime Movie

Video Files

RSS file extension

Rich Site Summary

Web Files

SAV file extension

Saved Game

Game Files

TTF file extension

TrueType Font

Font Files

UUE file extension

Uuencoded File

Encoded Files

VB file extension

VBScript File

Executable Files

VCD file extension

Virtual CD

Disk Image Files

WMA file extension

Windows Media Audio File

Audio Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files