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

ACCDB file extension

Access 2007 Database File

Database Files

ASX file extension

Microsoft ASF Redirector File

Video Files

DOC# file extension

Microsoft Word Document

Text Files

GAM file extension

Saved Game File

Game Files

GZ file extension

Gnu Zipped Archive

Compressed Files

IFF file extension

Interchange File Format

Audio Files

ISO file extension

Disc Image File

Disk Image Files

MDF file extension

Media Disc Image File

Disk Image Files

MP4 file extension

MPEG-4 Video File

Video Files

MSG file extension

Outlook Mail Message

Text Files

SDF file extension

Standard Data File

Data Files

TGA file extension

Targa Graphic

Raster Image Files

VB file extension

VBScript File

Executable Files

ZIPX file extension

Extended Zip File

Compressed Files

3DM file extension

Rhino 3D Model

3D Image Files