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

CSR file extension

Certificate Signing Request File

Web Files

CUE file extension

Cue Sheet File

Disk Image Files

GADGET file extension

Windows Gadget

Executable Files

GAM file extension

Saved Game File

Game Files

GBR file extension

Gerber File

Data Files

GIF file extension

Graphical Interchange Format File

Raster Image Files

ODT file extension

OpenDocument Text Document

Text Files

PRF file extension

Outlook Profile File

Settings Files

PY file extension

Python Script

Developer Files

SWF file extension

Shockwave Flash Movie

Video Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

TORRENT file extension

BitTorrent File

Misc Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files