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

CFG file extension

Configuration File

Settings Files

CUE file extension

Cue Sheet File

Disk Image Files

DXF file extension

Drawing Exchange Format File

CAD Files

EPUB file extension

Open eBook File

eBook Files

H file extension

C/C++/Objective-C Header File

Developer Files

IFF file extension

Interchange File Format

Audio Files

JPG file extension

JPEG Image

Raster Image Files

M4V file extension

iTunes Video File

Video Files

PCT file extension

Picture File

Layout Files

PDB file extension

Program Database

Database Files

VOB file extension

DVD Video Object File

Video Files

WPD file extension

WordPerfect Document

Text Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

3G2 file extension

3GPP2 Multimedia File

Video Files