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

CBR file extension

Comic Book RAR Archive

Compressed Files

DESKTHEMEPACK file extension

Windows 8 Desktop Theme Pack File

System Files

PDF file extension

Portable Document Format File

Layout Files

ODT file extension

OpenDocument Text Document

Text Files

RM file extension

Real Media File

Video Files

PIF file extension

Program Information File

Executable Files

IBOOKS file extension

Multi-Touch iBook

Data Files

WMA file extension

Windows Media Audio File

Audio Files

7Z file extension

7-Zip Compressed File

Compressed Files

YUV file extension

YUV Encoded Image File

Raster Image Files

DXF file extension

Drawing Exchange Format File

CAD Files

MOV file extension

Apple QuickTime Movie

Video Files

FNT file extension

Windows Font File

Font Files

PAGES file extension

Pages Document

Text Files

3DM file extension

Rhino 3D Model

3D Image Files