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

AZW file extension

Amazon Kindle eBook File

eBook Files

CPL file extension

Windows Control Panel Item

System Files

CUE file extension

Cue Sheet File

Disk Image Files

DEM file extension

Video Game Demo File

Game Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

FNT file extension

Windows Font File

Font Files

ICNS file extension

Mac OS X Icon Resource File

System Files

ICO file extension

Icon File

System Files

KMZ file extension

Google Earth Placemark File

GIS Files

ODT file extension

OpenDocument Text Document

Text Files

PS file extension

PostScript File

Vector Image Files

PY file extension

Python Script

Developer Files

THM file extension

Thumbnail Image File

Raster Image Files

VCF file extension

vCard File

Data Files

VOB file extension

DVD Video Object File

Video Files