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

CRX file extension

Chrome Extension

Plugin Files

TARGZ file extension

Compressed Tarball File

Compressed Files

ZIPX file extension

Extended Zip File

Compressed Files

PCT file extension

Picture File

Layout Files

LNK file extension

Windows File Shortcut

System Files

SRT file extension

SubRip Subtitle File

Video Files

PRF file extension

Outlook Profile File

Settings Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

GZ file extension

Gnu Zipped Archive

Compressed Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

TGA file extension

Targa Graphic

Raster Image Files

MP4 file extension

MPEG-4 Video File

Video Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

BMP file extension

Bitmap Image File

Raster Image Files

7Z file extension

7-Zip Compressed File

Compressed Files