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

AIF file extension

Audio Interchange File Format

Audio Files

DNG file extension

Digital Negative Image File

Camera Raw Files

ICNS file extension

Mac OS X Icon Resource File

System Files

INI file extension

Windows Initialization File

Settings Files

JAR file extension

Java Archive File

Executable Files

KML file extension

Keyhole Markup Language File

GIS Files

PART file extension

Partially Downloaded File

Misc Files

PCT file extension

Picture File

Layout Files

PDB file extension

Program Database

Database Files

PL file extension

Perl Script

Developer Files

SDF file extension

Standard Data File

Data Files

SH file extension

Bash Shell Script

Developer Files

SITX file extension

StuffIt X Archive

Compressed Files

SWF file extension

Shockwave Flash Movie

Video Files

VCD file extension

Virtual CD

Disk Image Files