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

DWG file extension

AutoCAD Drawing Database File

CAD Files

HTML file extension

Hypertext Markup Language File

Web Files

PIF file extension

Program Information File

Executable Files

7Z file extension

7-Zip Compressed File

Compressed Files

KMZ file extension

Google Earth Placemark File

GIS Files

ODT file extension

OpenDocument Text Document

Text Files

3DS file extension

3D Studio Scene

3D Image Files

GZ file extension

Gnu Zipped Archive

Compressed Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

AZW file extension

Amazon Kindle eBook File

eBook Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

ASPX file extension

Active Server Page Extended File

Web Files

PDF file extension

Portable Document Format File

Layout Files

MDB file extension

Microsoft Access Database

Database Files