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

GIF file extension

Graphical Interchange Format File

Raster Image Files

SDF file extension

Standard Data File

Data Files

KEY file extension

Keynote Presentation

Data Files

7Z file extension

7-Zip Compressed File

Compressed Files

EXE file extension

Windows Executable File

Executable Files

PPT file extension

PowerPoint Presentation

Data Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

PKG file extension

Mac OS X Installer Package

Compressed Files

FON file extension

Generic Font File

Font Files

PL file extension

Perl Script

Developer Files

DXF file extension

Drawing Exchange Format File

CAD Files

UUE file extension

Uuencoded File

Encoded Files

PRF file extension

Outlook Profile File

Settings Files

JS file extension

JavaScript File

Web Files

DAT file extension

Data File

Data Files