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

TAR file extension

Consolidated Unix File Archive

Data Files

MP3 file extension

MP3 Audio File

Audio Files

GADGET file extension

Windows Gadget

Executable Files

PIF file extension

Program Information File

Executable Files

EPUB file extension

Open eBook File

eBook Files

FON file extension

Generic Font File

Font Files

7Z file extension

7-Zip Compressed File

Compressed Files

SRT file extension

SubRip Subtitle File

Video Files

PART file extension

Partially Downloaded File

Misc Files

SITX file extension

StuffIt X Archive

Compressed Files

HTM file extension

Hypertext Markup Language File

Web Files

CSV file extension

Comma Separated Values File

Data Files

AI file extension

Adobe Illustrator File

Vector Image Files

MOV file extension

Apple QuickTime Movie

Video Files

PPS file extension

PowerPoint Slide Show

Data Files