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

7Z file extension

7-Zip Compressed File

Compressed Files

NES file extension

Nintendo (NES) ROM File

Game Files

C file extension

C/C++ Source Code File

Developer Files

BAT file extension

DOS Batch File

Executable Files

LNK file extension

Windows File Shortcut

System Files

GIF file extension

Graphical Interchange Format File

Raster Image Files

MDB file extension

Microsoft Access Database

Database Files

AZW file extension

Amazon Kindle eBook File

eBook Files

SYS file extension

Windows System File

System Files

CGI file extension

Common Gateway Interface Script

Executable Files

TEX file extension

LaTeX Source Document

Text Files

BMP file extension

Bitmap Image File

Raster Image Files

DAT file extension

Data File

Data Files

JS file extension

JavaScript File

Web Files

CPL file extension

Windows Control Panel Item

System Files