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

TEX file extension

LaTeX Source Document

Text Files

3DM file extension

Rhino 3D Model

3D Image Files

GADGET file extension

Windows Gadget

Executable Files

ZIP file extension

Zipped File

Compressed Files

7Z file extension

7-Zip Compressed File

Compressed Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

PAGES file extension

Pages Document

Text Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files

ASF file extension

Advanced Systems Format File

Video Files

C file extension

C/C++ Source Code File

Developer Files

CFM file extension

ColdFusion Markup File

Web Files

SYS file extension

Windows System File

System Files

CLASS file extension

Java Class File

Developer Files

GIF file extension

Graphical Interchange Format File

Raster Image Files

FLA file extension

Adobe Flash Animation

Developer Files