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

AZW file extension

Amazon Kindle eBook File

eBook Files

BMP file extension

Bitmap Image File

Raster Image Files

CBR file extension

Comic Book RAR Archive

Compressed Files

CFG file extension

Configuration File

Settings Files

DBF file extension

Database File

Database Files

IBOOKS file extension

Multi-Touch iBook

Data Files

ICNS file extension

Mac OS X Icon Resource File

System Files

JS file extension

JavaScript File

Web Files

MDB file extension

Microsoft Access Database

Database Files

MOV file extension

Apple QuickTime Movie

Video Files

MP3 file extension

MP3 Audio File

Audio Files

MPA file extension

MPEG-2 Audio File

Audio Files

SYS file extension

Windows System File

System Files

YUV file extension

YUV Encoded Image File

Raster Image Files

ZIP file extension

Zipped File

Compressed Files