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

PL file extension

Perl Script

Developer Files

HTML file extension

Hypertext Markup Language File

Web Files

VCD file extension

Virtual CD

Disk Image Files

ICS file extension

iCalendar File

Misc Files

WAV file extension

WAVE Audio File

Audio Files

PKG file extension

Mac OS X Installer Package

Compressed Files

3G2 file extension

3GPP2 Multimedia File

Video Files

7Z file extension

7-Zip Compressed File

Compressed Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

GADGET file extension

Windows Gadget

Executable Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

SLN file extension

Visual Studio Solution File

Developer Files

ACCDB file extension

Access 2007 Database File

Database Files

CRX file extension

Chrome Extension

Plugin Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files