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

AIF file extension

Audio Interchange File Format

Audio Files

APP file extension

Mac OS X Application

Executable Files

ASP file extension

Active Server Page

Web Files

CUE file extension

Cue Sheet File

Disk Image Files

DB file extension

Database File

Database Files

DDS file extension

DirectDraw Surface

Raster Image Files

GAM file extension

Saved Game File

Game Files

GIF file extension

Graphical Interchange Format File

Raster Image Files

GPX file extension

GPS Exchange File

GIS Files

JAR file extension

Java Archive File

Executable Files

JPG file extension

JPEG Image

Raster Image Files

JSP file extension

Java Server Page

Web Files

M4V file extension

iTunes Video File

Video Files

PART file extension

Partially Downloaded File

Misc Files

RSS file extension

Rich Site Summary

Web Files