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

ACCDB file extension

Access 2007 Database File

Database Files

AIF file extension

Audio Interchange File Format

Audio Files

DAT file extension

Data File

Data Files

GADGET file extension

Windows Gadget

Executable Files

IFF file extension

Interchange File Format

Audio Files

JS file extension

JavaScript File

Web Files

MID file extension

MIDI File

Audio Files

MSG file extension

Outlook Mail Message

Text Files

PAGES file extension

Pages Document

Text Files

PKG file extension

Mac OS X Installer Package

Compressed Files

PL file extension

Perl Script

Developer Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

RA file extension

Real Audio File

Audio Files

TEX file extension

LaTeX Source Document

Text Files

3G2 file extension

3GPP2 Multimedia File

Video Files