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

PL file extension

Perl Script

Developer Files

UUE file extension

Uuencoded File

Encoded Files

PAGES file extension

Pages Document

Text Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

SDF file extension

Standard Data File

Data Files

JAR file extension

Java Archive File

Executable Files

3DM file extension

Rhino 3D Model

3D Image Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

VCXPROJ file extension

Visual C++ Project

Developer Files

7Z file extension

7-Zip Compressed File

Compressed Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

JSP file extension

Java Server Page

Web Files

ICO file extension

Icon File

System Files

JS file extension

JavaScript File

Web Files