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

ASP file extension

Active Server Page

Web Files

CFG file extension

Configuration File

Settings Files

DEM file extension

Video Game Demo File

Game Files

DRV file extension

Device Driver

System Files

JS file extension

JavaScript File

Web Files

LOG file extension

Log File

Text Files

LUA file extension

Lua Source File

Developer Files

MID file extension

MIDI File

Audio Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

MSG file extension

Outlook Mail Message

Text Files

PNG file extension

Portable Network Graphic

Raster Image Files

PPT file extension

PowerPoint Presentation

Data Files

RPM file extension

Red Hat Package Manager File

Compressed Files

XML file extension

XML File

Data Files

3GP file extension

3GPP Multimedia File

Video Files