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

BIN file extension

Binary Disc Image

Disk Image Files

CSS file extension

Cascading Style Sheet

Web Files

DLL file extension

Dynamic Link Library

System Files

DNG file extension

Digital Negative Image File

Camera Raw Files

DRV file extension

Device Driver

System Files

EXE file extension

Windows Executable File

Executable Files

ICS file extension

iCalendar File

Misc Files

LNK file extension

Windows File Shortcut

System Files

M3U file extension

Media Playlist File

Audio Files

MSG file extension

Outlook Mail Message

Text Files

PIF file extension

Program Information File

Executable Files

RM file extension

Real Media File

Video Files

ROM file extension

N64 Game ROM File

Game Files

VCD file extension

Virtual CD

Disk Image Files

VOB file extension

DVD Video Object File

Video Files