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

ASX file extension

Microsoft ASF Redirector File

Video Files

DNG file extension

Digital Negative Image File

Camera Raw Files

DOC# file extension

Microsoft Word Document

Text Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

JAVA file extension

Java Source Code File

Developer Files

KML file extension

Keyhole Markup Language File

GIS Files

LNK file extension

Windows File Shortcut

System Files

M3U file extension

Media Playlist File

Audio Files

MAX file extension

3ds Max Scene File

3D Image Files

MDB file extension

Microsoft Access Database

Database Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

VCF file extension

vCard File

Data Files

WPD file extension

WordPerfect Document

Text Files

3G2 file extension

3GPP2 Multimedia File

Video Files