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

CPL file extension

Windows Control Panel Item

System Files

DMP file extension

Windows Memory Dump

System Files

FNT file extension

Windows Font File

Font Files

JS file extension

JavaScript File

Web Files

LUA file extension

Lua Source File

Developer Files

M4V file extension

iTunes Video File

Video Files

PCT file extension

Picture File

Layout Files

RM file extension

Real Media File

Video Files

ROM file extension

N64 Game ROM File

Game Files

SQL file extension

Structured Query Language Data File

Database Files

TEX file extension

LaTeX Source Document

Text Files

TIFF file extension

Tagged Image File Format

Raster Image Files

TOAST file extension

Toast Disc Image

Disk Image Files

TXT file extension

Plain Text File

Text Files

3G2 file extension

3GPP2 Multimedia File

Video Files