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

ACCDB file extension

Access 2007 Database File

Database Files

BAT file extension

DOS Batch File

Executable Files

DEM file extension

Video Game Demo File

Game Files

EPUB file extension

Open eBook File

eBook Files

GAM file extension

Saved Game File

Game Files

GPX file extension

GPS Exchange File

GIS Files

INI file extension

Windows Initialization File

Settings Files

MOV file extension

Apple QuickTime Movie

Video Files

MPG file extension

MPEG Video File

Video Files

NES file extension

Nintendo (NES) ROM File

Game Files

PHP file extension

PHP Source Code File

Web Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

SLN file extension

Visual Studio Solution File

Developer Files

7Z file extension

7-Zip Compressed File

Compressed Files