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

JAR file extension

Java Archive File

Executable Files

PY file extension

Python Script

Developer Files

KML file extension

Keyhole Markup Language File

GIS Files

JSP file extension

Java Server Page

Web Files

INI file extension

Windows Initialization File

Settings Files

LNK file extension

Windows File Shortcut

System Files

7Z file extension

7-Zip Compressed File

Compressed Files

CPP file extension

C++ Source Code File

Developer Files

DMP file extension

Windows Memory Dump

System Files

UUE file extension

Uuencoded File

Encoded Files

SRT file extension

SubRip Subtitle File

Video Files

TAR file extension

Consolidated Unix File Archive

Data Files

CPL file extension

Windows Control Panel Item

System Files

XML file extension

XML File

Data Files

ICO file extension

Icon File

System Files