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

CRX file extension

Chrome Extension

Plugin Files

EXE file extension

Windows Executable File

Executable Files

INI file extension

Windows Initialization File

Settings Files

KEY file extension

Keynote Presentation

Data Files

M3U file extension

Media Playlist File

Audio Files

MDF file extension

Media Disc Image File

Disk Image Files

RM file extension

Real Media File

Video Files

RPM file extension

Red Hat Package Manager File

Compressed Files

SH file extension

Bash Shell Script

Developer Files

UUE file extension

Uuencoded File

Encoded Files

VOB file extension

DVD Video Object File

Video Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

YUV file extension

YUV Encoded Image File

Raster Image Files

3DM file extension

Rhino 3D Model

3D Image Files