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

CRX file extension

Chrome Extension

Plugin Files

DXF file extension

Drawing Exchange Format File

CAD Files

FNT file extension

Windows Font File

Font Files

GPX file extension

GPS Exchange File

GIS Files

ICO file extension

Icon File

System Files

ISO file extension

Disc Image File

Disk Image Files

KEY file extension

Keynote Presentation

Data Files

KML file extension

Keyhole Markup Language File

GIS Files

M4A file extension

MPEG-4 Audio File

Audio Files

MDB file extension

Microsoft Access Database

Database Files

NES file extension

Nintendo (NES) ROM File

Game Files

PCT file extension

Picture File

Layout Files

PPT file extension

PowerPoint Presentation

Data Files

VCD file extension

Virtual CD

Disk Image Files

VCF file extension

vCard File

Data Files