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

CBR file extension

Comic Book RAR Archive

Compressed Files

CPL file extension

Windows Control Panel Item

System Files

CUE file extension

Cue Sheet File

Disk Image Files

DBF file extension

Database File

Database Files

DMP file extension

Windows Memory Dump

System Files

EXE file extension

Windows Executable File

Executable Files

GBR file extension

Gerber File

Data Files

H file extension

C/C++/Objective-C Header File

Developer Files

IBOOKS file extension

Multi-Touch iBook

Data Files

ICNS file extension

Mac OS X Icon Resource File

System Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

PKG file extension

Mac OS X Installer Package

Compressed Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

ZIPX file extension

Extended Zip File

Compressed Files

3DS file extension

3D Studio Scene

3D Image Files