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

ASF file extension

Advanced Systems Format File

Video Files

ASX file extension

Microsoft ASF Redirector File

Video Files

DBF file extension

Database File

Database Files

DEM file extension

Video Game Demo File

Game Files

DRV file extension

Device Driver

System Files

JPG file extension

JPEG Image

Raster Image Files

ODT file extension

OpenDocument Text Document

Text Files

PKG file extension

Mac OS X Installer Package

Compressed Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

RPM file extension

Red Hat Package Manager File

Compressed Files

SH file extension

Bash Shell Script

Developer Files

TAR file extension

Consolidated Unix File Archive

Data Files

THM file extension

Thumbnail Image File

Raster Image Files

3DM file extension

Rhino 3D Model

3D Image Files