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

ASF file extension

Advanced Systems Format File

Video Files

CBR file extension

Comic Book RAR Archive

Compressed Files

COM file extension

DOS Command File

Executable Files

CSS file extension

Cascading Style Sheet

Web Files

DDS file extension

DirectDraw Surface

Raster Image Files

DEB file extension

Debian Software Package

Compressed Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

PAGES file extension

Pages Document

Text Files

SAV file extension

Saved Game

Game Files

TEX file extension

LaTeX Source Document

Text Files

TTF file extension

TrueType Font

Font Files

TXT file extension

Plain Text File

Text Files

ZIP file extension

Zipped File

Compressed Files

3DS file extension

3D Studio Scene

3D Image Files

3GP file extension

3GPP Multimedia File

Video Files