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

CBR file extension

Comic Book RAR Archive

Compressed Files

COM file extension

DOS Command File

Executable Files

DXF file extension

Drawing Exchange Format File

CAD Files

FNT file extension

Windows Font File

Font Files

GPX file extension

GPS Exchange File

GIS Files

HTM file extension

Hypertext Markup Language File

Web Files

KML file extension

Keyhole Markup Language File

GIS Files

LOG file extension

Log File

Text Files

M3U file extension

Media Playlist File

Audio Files

MP3 file extension

MP3 Audio File

Audio Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

PKG file extension

Mac OS X Installer Package

Compressed Files

TTF file extension

TrueType Font

Font Files

VCD file extension

Virtual CD

Disk Image Files

WSF file extension

Windows Script File

Executable Files