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

ICS file extension

iCalendar File

Misc Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

HTM file extension

Hypertext Markup Language File

Web Files

MPG file extension

MPEG Video File

Video Files

ODT file extension

OpenDocument Text Document

Text Files

SYS file extension

Windows System File

System Files

JPG file extension

JPEG Image

Raster Image Files

SH file extension

Bash Shell Script

Developer Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

FON file extension

Generic Font File

Font Files

CFM file extension

ColdFusion Markup File

Web Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

MAX file extension

3ds Max Scene File

3D Image Files

THM file extension

Thumbnail Image File

Raster Image Files

7Z file extension

7-Zip Compressed File

Compressed Files