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

ACCDB file extension

Access 2007 Database File

Database Files

CLASS file extension

Java Class File

Developer Files

CSS file extension

Cascading Style Sheet

Web Files

DDS file extension

DirectDraw Surface

Raster Image Files

DXF file extension

Drawing Exchange Format File

CAD Files

GIF file extension

Graphical Interchange Format File

Raster Image Files

MID file extension

MIDI File

Audio Files

MSI file extension

Windows Installer Package

Misc Files

NES file extension

Nintendo (NES) ROM File

Game Files

SH file extension

Bash Shell Script

Developer Files

SQL file extension

Structured Query Language Data File

Database Files

TAR file extension

Consolidated Unix File Archive

Data Files

VOB file extension

DVD Video Object File

Video Files

ZIP file extension

Zipped File

Compressed Files

ZIPX file extension

Extended Zip File

Compressed Files