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

C file extension

C/C++ Source Code File

Developer Files

CAB file extension

Windows Cabinet File

System Files

CLASS file extension

Java Class File

Developer Files

DAT file extension

Data File

Data Files

GADGET file extension

Windows Gadget

Executable Files

GIF file extension

Graphical Interchange Format File

Raster Image Files

GZ file extension

Gnu Zipped Archive

Compressed Files

PDF file extension

Portable Document Format File

Layout Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

PPS file extension

PowerPoint Slide Show

Data Files

RA file extension

Real Audio File

Audio Files

RTF file extension

Rich Text Format File

Text Files

SRT file extension

SubRip Subtitle File

Video Files

TIF file extension

Tagged Image File

Raster Image Files

TIFF file extension

Tagged Image File Format

Raster Image Files