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

XLR file extension

Works Spreadsheet

Spreadsheet Files

MAX file extension

3ds Max Scene File

3D Image Files

HTML file extension

Hypertext Markup Language File

Web Files

SITX file extension

StuffIt X Archive

Compressed Files

CPL file extension

Windows Control Panel Item

System Files

3DM file extension

Rhino 3D Model

3D Image Files

SLN file extension

Visual Studio Solution File

Developer Files

RA file extension

Real Audio File

Audio Files

DB file extension

Database File

Database Files

CRX file extension

Chrome Extension

Plugin Files

LOG file extension

Log File

Text Files

PHP file extension

PHP Source Code File

Web Files

BMP file extension

Bitmap Image File

Raster Image Files

TIFF file extension

Tagged Image File Format

Raster Image Files

7Z file extension

7-Zip Compressed File

Compressed Files