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

BAK file extension

Backup File

Backup Files

FON file extension

Generic Font File

Font Files

GADGET file extension

Windows Gadget

Executable Files

GED file extension

GEDCOM Genealogy Data File

Data Files

JSP file extension

Java Server Page

Web Files

KMZ file extension

Google Earth Placemark File

GIS Files

LUA file extension

Lua Source File

Developer Files

MID file extension

MIDI File

Audio Files

ODT file extension

OpenDocument Text Document

Text Files

PPS file extension

PowerPoint Slide Show

Data Files

RTF file extension

Rich Text Format File

Text Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

TTF file extension

TrueType Font

Font Files

3DM file extension

Rhino 3D Model

3D Image Files