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

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

PART file extension

Partially Downloaded File

Misc Files

TOAST file extension

Toast Disc Image

Disk Image Files

WMA file extension

Windows Media Audio File

Audio Files

CFM file extension

ColdFusion Markup File

Web Files

MOV file extension

Apple QuickTime Movie

Video Files

7Z file extension

7-Zip Compressed File

Compressed Files

ACCDB file extension

Access 2007 Database File

Database Files

SDF file extension

Standard Data File

Data Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

SAV file extension

Saved Game

Game Files

CSS file extension

Cascading Style Sheet

Web Files

PS file extension

PostScript File

Vector Image Files

ZIP file extension

Zipped File

Compressed Files

KEY file extension

Keynote Presentation

Data Files