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

JSP file extension

Java Server Page

Web Files

WAV file extension

WAVE Audio File

Audio Files

PPT file extension

PowerPoint Presentation

Data Files

RSS file extension

Rich Site Summary

Web Files

GAM file extension

Saved Game File

Game Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

DEB file extension

Debian Software Package

Compressed Files

7Z file extension

7-Zip Compressed File

Compressed Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

INDD file extension

Adobe InDesign Document

Layout Files

DAT file extension

Data File

Data Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

COM file extension

DOS Command File

Executable Files

MID file extension

MIDI File

Audio Files

MP4 file extension

MPEG-4 Video File

Video Files