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

CUR file extension

Windows Cursor

System Files

BMP file extension

Bitmap Image File

Raster Image Files

YUV file extension

YUV Encoded Image File

Raster Image Files

SDF file extension

Standard Data File

Data Files

SWF file extension

Shockwave Flash Movie

Video Files

7Z file extension

7-Zip Compressed File

Compressed Files

MAX file extension

3ds Max Scene File

3D Image Files

GIF file extension

Graphical Interchange Format File

Raster Image Files

M3U file extension

Media Playlist File

Audio Files

PPT file extension

PowerPoint Presentation

Data Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

3GP file extension

3GPP Multimedia File

Video Files

BAT file extension

DOS Batch File

Executable Files

DTD file extension

Document Type Definition File

Developer Files