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

C file extension

C/C++ Source Code File

Developer Files

CPL file extension

Windows Control Panel Item

System Files

CUE file extension

Cue Sheet File

Disk Image Files

CUR file extension

Windows Cursor

System Files

GED file extension

GEDCOM Genealogy Data File

Data Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

LUA file extension

Lua Source File

Developer Files

M4V file extension

iTunes Video File

Video Files

MID file extension

MIDI File

Audio Files

PIF file extension

Program Information File

Executable Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

PY file extension

Python Script

Developer Files

SAV file extension

Saved Game

Game Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files