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

C file extension

C/C++ Source Code File

Developer Files

DB file extension

Database File

Database Files

DEM file extension

Video Game Demo File

Game Files

DESKTHEMEPACK file extension

Windows 8 Desktop Theme Pack File

System Files

FNT file extension

Windows Font File

Font Files

HTML file extension

Hypertext Markup Language File

Web Files

KEY file extension

Keynote Presentation

Data Files

KMZ file extension

Google Earth Placemark File

GIS Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

MPG file extension

MPEG Video File

Video Files

PRF file extension

Outlook Profile File

Settings Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

VCXPROJ file extension

Visual C++ Project

Developer Files

WMA file extension

Windows Media Audio File

Audio Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files