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

APK file extension

Android Package File

Executable Files

GZ file extension

Gnu Zipped Archive

Compressed Files

WMA file extension

Windows Media Audio File

Audio Files

7Z file extension

7-Zip Compressed File

Compressed Files

ZIPX file extension

Extended Zip File

Compressed Files

JS file extension

JavaScript File

Web Files

CAB file extension

Windows Cabinet File

System Files

PPS file extension

PowerPoint Slide Show

Data Files

CUR file extension

Windows Cursor

System Files

SAV file extension

Saved Game

Game Files

3DM file extension

Rhino 3D Model

3D Image Files

ICO file extension

Icon File

System Files

CSV file extension

Comma Separated Values File

Data Files

FNT file extension

Windows Font File

Font Files