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

CUE file extension

Cue Sheet File

Disk Image Files

SRT file extension

SubRip Subtitle File

Video Files

PCT file extension

Picture File

Layout Files

7Z file extension

7-Zip Compressed File

Compressed Files

H file extension

C/C++/Objective-C Header File

Developer Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

SWF file extension

Shockwave Flash Movie

Video Files

KMZ file extension

Google Earth Placemark File

GIS Files

FON file extension

Generic Font File

Font Files

DRV file extension

Device Driver

System Files

VCF file extension

vCard File

Data Files

ROM file extension

N64 Game ROM File

Game Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

TIF file extension

Tagged Image File

Raster Image Files

PNG file extension

Portable Network Graphic

Raster Image Files