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

PY file extension

Python Script

Developer Files

SH file extension

Bash Shell Script

Developer Files

XML file extension

XML File

Data Files

WMA file extension

Windows Media Audio File

Audio Files

AI file extension

Adobe Illustrator File

Vector Image Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

PRF file extension

Outlook Profile File

Settings Files

APP file extension

Mac OS X Application

Executable Files

NES file extension

Nintendo (NES) ROM File

Game Files

7Z file extension

7-Zip Compressed File

Compressed Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

YUV file extension

YUV Encoded Image File

Raster Image Files

DOC file extension

Microsoft Word Document

Text Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

CGI file extension

Common Gateway Interface Script

Executable Files