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

AI file extension

Adobe Illustrator File

Vector Image Files

ASX file extension

Microsoft ASF Redirector File

Video Files

CAB file extension

Windows Cabinet File

System Files

CLASS file extension

Java Class File

Developer Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

GZ file extension

Gnu Zipped Archive

Compressed Files

H file extension

C/C++/Objective-C Header File

Developer Files

LNK file extension

Windows File Shortcut

System Files

MDF file extension

Media Disc Image File

Disk Image Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

PL file extension

Perl Script

Developer Files

SAV file extension

Saved Game

Game Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

XML file extension

XML File

Data Files

3G2 file extension

3GPP2 Multimedia File

Video Files