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

APP file extension

Mac OS X Application

Executable Files

DEB file extension

Debian Software Package

Compressed Files

GAM file extension

Saved Game File

Game Files

H file extension

C/C++/Objective-C Header File

Developer Files

HTM file extension

Hypertext Markup Language File

Web Files

HTML file extension

Hypertext Markup Language File

Web Files

JAVA file extension

Java Source Code File

Developer Files

KMZ file extension

Google Earth Placemark File

GIS Files

PDB file extension

Program Database

Database Files

PIF file extension

Program Information File

Executable Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

TMP file extension

Temporary File

Backup Files

TTF file extension

TrueType Font

Font Files

VOB file extension

DVD Video Object File

Video Files

3GP file extension

3GPP Multimedia File

Video Files