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

BMP file extension

Bitmap Image File

Raster Image Files

CPP file extension

C++ Source Code File

Developer Files

DEB file extension

Debian Software Package

Compressed Files

DTD file extension

Document Type Definition File

Developer Files

GPX file extension

GPS Exchange File

GIS Files

ICS file extension

iCalendar File

Misc Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

MSI file extension

Windows Installer Package

Misc Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

RA file extension

Real Audio File

Audio Files

RTF file extension

Rich Text Format File

Text Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

TORRENT file extension

BitTorrent File

Misc Files

VCF file extension

vCard File

Data Files

3DM file extension

Rhino 3D Model

3D Image Files