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

DXF file extension

Drawing Exchange Format File

CAD Files

EXE file extension

Windows Executable File

Executable Files

FNT file extension

Windows Font File

Font Files

GADGET file extension

Windows Gadget

Executable Files

GZ file extension

Gnu Zipped Archive

Compressed Files

H file extension

C/C++/Objective-C Header File

Developer Files

ICO file extension

Icon File

System Files

ICS file extension

iCalendar File

Misc Files

PKG file extension

Mac OS X Installer Package

Compressed Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

PS file extension

PostScript File

Vector Image Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

TOAST file extension

Toast Disc Image

Disk Image Files

TXT file extension

Plain Text File

Text Files

UUE file extension

Uuencoded File

Encoded Files