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

APP file extension

Mac OS X Application

Executable Files

ASP file extension

Active Server Page

Web Files

ASX file extension

Microsoft ASF Redirector File

Video Files

DMP file extension

Windows Memory Dump

System Files

ICO file extension

Icon File

System Files

KMZ file extension

Google Earth Placemark File

GIS Files

LOG file extension

Log File

Text Files

M4A file extension

MPEG-4 Audio File

Audio Files

MPA file extension

MPEG-2 Audio File

Audio Files

ODT file extension

OpenDocument Text Document

Text Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

PPT file extension

PowerPoint Presentation

Data Files

TIF file extension

Tagged Image File

Raster Image Files

TIFF file extension

Tagged Image File Format

Raster Image Files

WMA file extension

Windows Media Audio File

Audio Files