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

CER file extension

Internet Security Certificate

Web Files

CFM file extension

ColdFusion Markup File

Web Files

DBF file extension

Database File

Database Files

DEM file extension

Video Game Demo File

Game Files

DRV file extension

Device Driver

System Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

DXF file extension

Drawing Exchange Format File

CAD Files

GZ file extension

Gnu Zipped Archive

Compressed Files

IFF file extension

Interchange File Format

Audio Files

MP3 file extension

MP3 Audio File

Audio Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

OTF file extension

OpenType Font

Font Files

UUE file extension

Uuencoded File

Encoded Files

3GP file extension

3GPP Multimedia File

Video Files