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

ASX file extension

Microsoft ASF Redirector File

Video Files

DNG file extension

Digital Negative Image File

Camera Raw Files

GED file extension

GEDCOM Genealogy Data File

Data Files

GPX file extension

GPS Exchange File

GIS Files

IBOOKS file extension

Multi-Touch iBook

Data Files

KMZ file extension

Google Earth Placemark File

GIS Files

M3U file extension

Media Playlist File

Audio Files

MSG file extension

Outlook Mail Message

Text Files

PS file extension

PostScript File

Vector Image Files

SAV file extension

Saved Game

Game Files

THM file extension

Thumbnail Image File

Raster Image Files

TTF file extension

TrueType Font

Font Files

TXT file extension

Plain Text File

Text Files

VCF file extension

vCard File

Data Files

3GP file extension

3GPP Multimedia File

Video Files