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

3G2 file extension

3GPP2 Multimedia File

Video Files

TARGZ file extension

Compressed Tarball File

Compressed Files

CLASS file extension

Java Class File

Developer Files

JS file extension

JavaScript File

Web Files

ASX file extension

Microsoft ASF Redirector File

Video Files

ASF file extension

Advanced Systems Format File

Video Files

WAV file extension

WAVE Audio File

Audio Files

7Z file extension

7-Zip Compressed File

Compressed Files

IBOOKS file extension

Multi-Touch iBook

Data Files

CPP file extension

C++ Source Code File

Developer Files

H file extension

C/C++/Objective-C Header File

Developer Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

MDB file extension

Microsoft Access Database

Database Files

GPX file extension

GPS Exchange File

GIS Files

ZIPX file extension

Extended Zip File

Compressed Files