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

VOB file extension

DVD Video Object File

Video Files

INI file extension

Windows Initialization File

Settings Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

MPA file extension

MPEG-2 Audio File

Audio Files

DESKTHEMEPACK file extension

Windows 8 Desktop Theme Pack File

System Files

INDD file extension

Adobe InDesign Document

Layout Files

JS file extension

JavaScript File

Web Files

7Z file extension

7-Zip Compressed File

Compressed Files

SWF file extension

Shockwave Flash Movie

Video Files

CFM file extension

ColdFusion Markup File

Web Files

MOBI file extension

Mobipocket eBook

eBook Files

DRV file extension

Device Driver

System Files

DBF file extension

Database File

Database Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

OTF file extension

OpenType Font

Font Files