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

SLN file extension

Visual Studio Solution File

Developer Files

CPL file extension

Windows Control Panel Item

System Files

PNG file extension

Portable Network Graphic

Raster Image Files

MID file extension

MIDI File

Audio Files

SH file extension

Bash Shell Script

Developer Files

CFM file extension

ColdFusion Markup File

Web Files

APP file extension

Mac OS X Application

Executable Files

ICO file extension

Icon File

System Files

3DM file extension

Rhino 3D Model

3D Image Files

7Z file extension

7-Zip Compressed File

Compressed Files

TTF file extension

TrueType Font

Font Files

ODT file extension

OpenDocument Text Document

Text Files

JPG file extension

JPEG Image

Raster Image Files

PL file extension

Perl Script

Developer Files