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

COM file extension

DOS Command File

Executable Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

DRV file extension

Device Driver

System Files

DTD file extension

Document Type Definition File

Developer Files

H file extension

C/C++/Objective-C Header File

Developer Files

MAX file extension

3ds Max Scene File

3D Image Files

MPG file extension

MPEG Video File

Video Files

PS file extension

PostScript File

Vector Image Files

TGA file extension

Targa Graphic

Raster Image Files

WMA file extension

Windows Media Audio File

Audio Files

WSF file extension

Windows Script File

Executable Files

3GP file extension

3GPP Multimedia File

Video Files