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

7Z file extension

7-Zip Compressed File

Compressed Files

CER file extension

Internet Security Certificate

Web Files

PNG file extension

Portable Network Graphic

Raster Image Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

GADGET file extension

Windows Gadget

Executable Files

MPG file extension

MPEG Video File

Video Files

DB file extension

Database File

Database Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

YUV file extension

YUV Encoded Image File

Raster Image Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

CSR file extension

Certificate Signing Request File

Web Files

KMZ file extension

Google Earth Placemark File

GIS Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

PIF file extension

Program Information File

Executable Files

DEM file extension

Video Game Demo File

Game Files