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

TEX file extension

LaTeX Source Document

Text Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

7Z file extension

7-Zip Compressed File

Compressed Files

ROM file extension

N64 Game ROM File

Game Files

PCT file extension

Picture File

Layout Files

NES file extension

Nintendo (NES) ROM File

Game Files

CFG file extension

Configuration File

Settings Files

CUR file extension

Windows Cursor

System Files

3DS file extension

3D Studio Scene

3D Image Files

3GP file extension

3GPP Multimedia File

Video Files

DOC file extension

Microsoft Word Document

Text Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

DMP file extension

Windows Memory Dump

System Files

LNK file extension

Windows File Shortcut

System Files

DOC# file extension

Microsoft Word Document

Text Files