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

AIF file extension

Audio Interchange File Format

Audio Files

AZW file extension

Amazon Kindle eBook File

eBook Files

INDD file extension

Adobe InDesign Document

Layout Files

JSP file extension

Java Server Page

Web Files

KMZ file extension

Google Earth Placemark File

GIS Files

LOG file extension

Log File

Text Files

MID file extension

MIDI File

Audio Files

NES file extension

Nintendo (NES) ROM File

Game Files

RPM file extension

Red Hat Package Manager File

Compressed Files

SRT file extension

SubRip Subtitle File

Video Files

TEX file extension

LaTeX Source Document

Text Files

WMA file extension

Windows Media Audio File

Audio Files

WSF file extension

Windows Script File

Executable Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files