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

AI file extension

Adobe Illustrator File

Vector Image Files

APK file extension

Android Package File

Executable Files

DOC# file extension

Microsoft Word Document

Text Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

GPX file extension

GPS Exchange File

GIS Files

HTM file extension

Hypertext Markup Language File

Web Files

ICO file extension

Icon File

System Files

KML file extension

Keyhole Markup Language File

GIS Files

KMZ file extension

Google Earth Placemark File

GIS Files

PCT file extension

Picture File

Layout Files

PY file extension

Python Script

Developer Files

SYS file extension

Windows System File

System Files

TEX file extension

LaTeX Source Document

Text Files

3G2 file extension

3GPP2 Multimedia File

Video Files