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

7Z file extension

7-Zip Compressed File

Compressed Files

AZW file extension

Amazon Kindle eBook File

eBook Files

NES file extension

Nintendo (NES) ROM File

Game Files

XML file extension

XML File

Data Files

MP4 file extension

MPEG-4 Video File

Video Files

JAR file extension

Java Archive File

Executable Files

TTF file extension

TrueType Font

Font Files

JS file extension

JavaScript File

Web Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files

PPS file extension

PowerPoint Slide Show

Data Files

RSS file extension

Rich Site Summary

Web Files

FLA file extension

Adobe Flash Animation

Developer Files

GADGET file extension

Windows Gadget

Executable Files

RA file extension

Real Audio File

Audio Files

DWG file extension

AutoCAD Drawing Database File

CAD Files