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

7Z file extension

7-Zip Compressed File

Compressed Files

OTF file extension

OpenType Font

Font Files

ICNS file extension

Mac OS X Icon Resource File

System Files

VB file extension

VBScript File

Executable Files

SQL file extension

Structured Query Language Data File

Database Files

INI file extension

Windows Initialization File

Settings Files

3DS file extension

3D Studio Scene

3D Image Files

CFM file extension

ColdFusion Markup File

Web Files

HTM file extension

Hypertext Markup Language File

Web Files

GADGET file extension

Windows Gadget

Executable Files

ASP file extension

Active Server Page

Web Files

VCF file extension

vCard File

Data Files

IFF file extension

Interchange File Format

Audio Files

FON file extension

Generic Font File

Font Files

CSS file extension

Cascading Style Sheet

Web Files