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

COM file extension

DOS Command File

Executable Files

CBR file extension

Comic Book RAR Archive

Compressed Files

M3U file extension

Media Playlist File

Audio Files

SDF file extension

Standard Data File

Data Files

PHP file extension

PHP Source Code File

Web Files

MP4 file extension

MPEG-4 Video File

Video Files

JPG file extension

JPEG Image

Raster Image Files

7Z file extension

7-Zip Compressed File

Compressed Files

WSF file extension

Windows Script File

Executable Files

IBOOKS file extension

Multi-Touch iBook

Data Files

TIF file extension

Tagged Image File

Raster Image Files

SH file extension

Bash Shell Script

Developer Files

PL file extension

Perl Script

Developer Files

GPX file extension

GPS Exchange File

GIS Files

MOBI file extension

Mobipocket eBook

eBook Files