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

CGI file extension

Common Gateway Interface Script

Executable Files

DAT file extension

Data File

Data Files

DB file extension

Database File

Database Files

FLV file extension

Flash Video File

Video Files

GPX file extension

GPS Exchange File

GIS Files

ICO file extension

Icon File

System Files

JPG file extension

JPEG Image

Raster Image Files

LUA file extension

Lua Source File

Developer Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

MOV file extension

Apple QuickTime Movie

Video Files

MPA file extension

MPEG-2 Audio File

Audio Files

RA file extension

Real Audio File

Audio Files

VB file extension

VBScript File

Executable Files

WMA file extension

Windows Media Audio File

Audio Files

3DM file extension

Rhino 3D Model

3D Image Files