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

KML file extension

Keyhole Markup Language File

GIS Files

7Z file extension

7-Zip Compressed File

Compressed Files

DESKTHEMEPACK file extension

Windows 8 Desktop Theme Pack File

System Files

ASP file extension

Active Server Page

Web Files

VOB file extension

DVD Video Object File

Video Files

LUA file extension

Lua Source File

Developer Files

SDF file extension

Standard Data File

Data Files

DBF file extension

Database File

Database Files

AIF file extension

Audio Interchange File Format

Audio Files

PCT file extension

Picture File

Layout Files

TIFF file extension

Tagged Image File Format

Raster Image Files

PHP file extension

PHP Source Code File

Web Files

YUV file extension

YUV Encoded Image File

Raster Image Files

AZW file extension

Amazon Kindle eBook File

eBook Files

GED file extension

GEDCOM Genealogy Data File

Data Files