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

DEB file extension

Debian Software Package

Compressed Files

LUA file extension

Lua Source File

Developer Files

DDS file extension

DirectDraw Surface

Raster Image Files

CBR file extension

Comic Book RAR Archive

Compressed Files

TIFF file extension

Tagged Image File Format

Raster Image Files

CSR file extension

Certificate Signing Request File

Web Files

7Z file extension

7-Zip Compressed File

Compressed Files

MDF file extension

Media Disc Image File

Disk Image Files

SQL file extension

Structured Query Language Data File

Database Files

JS file extension

JavaScript File

Web Files

DEM file extension

Video Game Demo File

Game Files

MSI file extension

Windows Installer Package

Misc Files

OTF file extension

OpenType Font

Font Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

GIF file extension

Graphical Interchange Format File

Raster Image Files