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

ASPX file extension

Active Server Page Extended File

Web Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

CSR file extension

Certificate Signing Request File

Web Files

DOC# file extension

Microsoft Word Document

Text Files

FNT file extension

Windows Font File

Font 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

ICS file extension

iCalendar File

Misc Files

INI file extension

Windows Initialization File

Settings Files

M4A file extension

MPEG-4 Audio File

Audio Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

SAV file extension

Saved Game

Game Files

WMA file extension

Windows Media Audio File

Audio Files

YUV file extension

YUV Encoded Image File

Raster Image Files