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

JS file extension

JavaScript File

Web Files

RTF file extension

Rich Text Format File

Text Files

GBR file extension

Gerber File

Data Files

ROM file extension

N64 Game ROM File

Game Files

RSS file extension

Rich Site Summary

Web Files

ZIPX file extension

Extended Zip File

Compressed Files

AI file extension

Adobe Illustrator File

Vector Image Files

DXF file extension

Drawing Exchange Format File

CAD Files

PL file extension

Perl Script

Developer Files

H file extension

C/C++/Objective-C Header File

Developer Files

7Z file extension

7-Zip Compressed File

Compressed Files

TIFF file extension

Tagged Image File Format

Raster Image Files

INDD file extension

Adobe InDesign Document

Layout Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

PHP file extension

PHP Source Code File

Web Files