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

CSS file extension

Cascading Style Sheet

Web Files

H file extension

C/C++/Objective-C Header File

Developer Files

DBF file extension

Database File

Database Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

7Z file extension

7-Zip Compressed File

Compressed Files

FLA file extension

Adobe Flash Animation

Developer Files

ICNS file extension

Mac OS X Icon Resource File

System Files

WAV file extension

WAVE Audio File

Audio Files

RA file extension

Real Audio File

Audio Files

GED file extension

GEDCOM Genealogy Data File

Data Files

PCT file extension

Picture File

Layout Files

SLN file extension

Visual Studio Solution File

Developer Files

VCXPROJ file extension

Visual C++ Project

Developer Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

IFF file extension

Interchange File Format

Audio Files