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

M file extension

Objective-C Implementation File

Developer Files

WMV file extension

Windows Media Video File

Video Files

LUA file extension

Lua Source File

Developer Files

GED file extension

GEDCOM Genealogy Data File

Data Files

DEM file extension

Video Game Demo File

Game Files

7Z file extension

7-Zip Compressed File

Compressed Files

DLL file extension

Dynamic Link Library

System Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

JAR file extension

Java Archive File

Executable Files

M4V file extension

iTunes Video File

Video Files

IFF file extension

Interchange File Format

Audio Files

PL file extension

Perl Script

Developer Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

PDF file extension

Portable Document Format File

Layout Files

ZIPX file extension

Extended Zip File

Compressed Files