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

MOV file extension

Apple QuickTime Movie

Video Files

CAB file extension

Windows Cabinet File

System Files

GIF file extension

Graphical Interchange Format File

Raster Image Files

EXE file extension

Windows Executable File

Executable Files

AI file extension

Adobe Illustrator File

Vector Image Files

RSS file extension

Rich Site Summary

Web Files

WAV file extension

WAVE Audio File

Audio Files

TOAST file extension

Toast Disc Image

Disk Image Files

DBF file extension

Database File

Database Files

7Z file extension

7-Zip Compressed File

Compressed Files

PCT file extension

Picture File

Layout Files

MID file extension

MIDI File

Audio Files

HTML file extension

Hypertext Markup Language File

Web Files

SLN file extension

Visual Studio Solution File

Developer Files

PPT file extension

PowerPoint Presentation

Data Files