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

MAX file extension

3ds Max Scene File

3D Image Files

NES file extension

Nintendo (NES) ROM File

Game Files

3G2 file extension

3GPP2 Multimedia File

Video Files

TGA file extension

Targa Graphic

Raster Image Files

CLASS file extension

Java Class File

Developer Files

WMA file extension

Windows Media Audio File

Audio Files

TOAST file extension

Toast Disc Image

Disk Image Files

HTM file extension

Hypertext Markup Language File

Web Files

7Z file extension

7-Zip Compressed File

Compressed Files

CSR file extension

Certificate Signing Request File

Web Files

CGI file extension

Common Gateway Interface Script

Executable Files

SWF file extension

Shockwave Flash Movie

Video Files

CFM file extension

ColdFusion Markup File

Web Files

APK file extension

Android Package File

Executable Files

MOV file extension

Apple QuickTime Movie

Video Files