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

AI file extension

Adobe Illustrator File

Vector Image Files

BIN file extension

Binary Disc Image

Disk Image Files

DEM file extension

Video Game Demo File

Game Files

FLV file extension

Flash Video File

Video Files

GAM file extension

Saved Game File

Game Files

IFF file extension

Interchange File Format

Audio Files

KEY file extension

Keynote Presentation

Data Files

LUA file extension

Lua Source File

Developer Files

M4V file extension

iTunes Video File

Video Files

MDF file extension

Media Disc Image File

Disk Image Files

PCT file extension

Picture File

Layout Files

PL file extension

Perl Script

Developer Files

ROM file extension

N64 Game ROM File

Game Files

ZIP file extension

Zipped File

Compressed Files

7Z file extension

7-Zip Compressed File

Compressed Files