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

DB file extension

Database File

Database Files

EPUB file extension

Open eBook File

eBook Files

GED file extension

GEDCOM Genealogy Data File

Data Files

IBOOKS file extension

Multi-Touch iBook

Data Files

ICNS file extension

Mac OS X Icon Resource File

System Files

ICS file extension

iCalendar File

Misc Files

MOV file extension

Apple QuickTime Movie

Video Files

NES file extension

Nintendo (NES) ROM File

Game Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

PDB file extension

Program Database

Database Files

RTF file extension

Rich Text Format File

Text Files

TIF file extension

Tagged Image File

Raster Image Files

TORRENT file extension

BitTorrent File

Misc Files

VB file extension

VBScript File

Executable Files

3G2 file extension

3GPP2 Multimedia File

Video Files