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

ASX file extension

Microsoft ASF Redirector File

Video Files

BMP file extension

Bitmap Image File

Raster Image Files

CBR file extension

Comic Book RAR Archive

Compressed Files

CFG file extension

Configuration File

Settings Files

DAT file extension

Data File

Data Files

DBF file extension

Database File

Database Files

DTD file extension

Document Type Definition File

Developer Files

FON file extension

Generic Font File

Font Files

ICS file extension

iCalendar File

Misc Files

IFF file extension

Interchange File Format

Audio Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

MP3 file extension

MP3 Audio File

Audio Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

3DS file extension

3D Studio Scene

3D Image Files