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

AZW file extension

Amazon Kindle eBook File

eBook Files

DNG file extension

Digital Negative Image File

Camera Raw Files

FLV file extension

Flash Video File

Video Files

FNT file extension

Windows Font File

Font Files

FON file extension

Generic Font File

Font Files

ICNS file extension

Mac OS X Icon Resource File

System Files

MSI file extension

Windows Installer Package

Misc Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

RTF file extension

Rich Text Format File

Text Files

TARGZ file extension

Compressed Tarball File

Compressed Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

VOB file extension

DVD Video Object File

Video Files

WAV file extension

WAVE Audio File

Audio Files

XCODEPROJ file extension

Xcode Project

Developer Files