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

AZW file extension

Amazon Kindle eBook File

eBook Files

DOC# file extension

Microsoft Word Document

Text Files

DRV file extension

Device Driver

System Files

GAM file extension

Saved Game File

Game Files

KMZ file extension

Google Earth Placemark File

GIS Files

MP3 file extension

MP3 Audio File

Audio Files

ODT file extension

OpenDocument Text Document

Text Files

OTF file extension

OpenType Font

Font Files

PCT file extension

Picture File

Layout Files

SWF file extension

Shockwave Flash Movie

Video Files

TOAST file extension

Toast Disc Image

Disk Image Files

VCF file extension

vCard File

Data Files

WAV file extension

WAVE Audio File

Audio Files

3DM file extension

Rhino 3D Model

3D Image Files

3GP file extension

3GPP Multimedia File

Video Files