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

DWG file extension

AutoCAD Drawing Database File

CAD Files

KMZ file extension

Google Earth Placemark File

GIS Files

ROM file extension

N64 Game ROM File

Game Files

H file extension

C/C++/Objective-C Header File

Developer Files

MSG file extension

Outlook Mail Message

Text Files

APK file extension

Android Package File

Executable Files

GPX file extension

GPS Exchange File

GIS Files

7Z file extension

7-Zip Compressed File

Compressed Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files

DOC file extension

Microsoft Word Document

Text Files

SITX file extension

StuffIt X Archive

Compressed Files

RSS file extension

Rich Site Summary

Web Files

GADGET file extension

Windows Gadget

Executable Files

ASP file extension

Active Server Page

Web Files

YUV file extension

YUV Encoded Image File

Raster Image Files