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

PPTX file extension

PowerPoint Open XML Presentation

Data Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

RSS file extension

Rich Site Summary

Web Files

WPD file extension

WordPerfect Document

Text Files

HTML file extension

Hypertext Markup Language File

Web Files

7Z file extension

7-Zip Compressed File

Compressed Files

BAT file extension

DOS Batch File

Executable Files

JS file extension

JavaScript File

Web Files

VCF file extension

vCard File

Data Files

DOC# file extension

Microsoft Word Document

Text Files

CLASS file extension

Java Class File

Developer Files

3G2 file extension

3GPP2 Multimedia File

Video Files

GBR file extension

Gerber File

Data Files