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

DAT file extension

Data File

Data Files

DBF file extension

Database File

Database Files

DNG file extension

Digital Negative Image File

Camera Raw Files

EXE file extension

Windows Executable File

Executable Files

GAM file extension

Saved Game File

Game Files

GPX file extension

GPS Exchange File

GIS Files

IBOOKS file extension

Multi-Touch iBook

Data Files

KML file extension

Keyhole Markup Language File

GIS Files

MID file extension

MIDI File

Audio Files

OTF file extension

OpenType Font

Font Files

PCT file extension

Picture File

Layout Files

PHP file extension

PHP Source Code File

Web Files

PRF file extension

Outlook Profile File

Settings Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

SWF file extension

Shockwave Flash Movie

Video Files