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

ASP file extension

Active Server Page

Web Files

CFG file extension

Configuration File

Settings Files

DEM file extension

Video Game Demo File

Game Files

DOC# file extension

Microsoft Word Document

Text Files

JPG file extension

JPEG Image

Raster Image Files

MDB file extension

Microsoft Access Database

Database Files

MP4 file extension

MPEG-4 Video File

Video Files

OTF file extension

OpenType Font

Font Files

PIF file extension

Program Information File

Executable Files

RM file extension

Real Media File

Video Files

RPM file extension

Red Hat Package Manager File

Compressed Files

VB file extension

VBScript File

Executable Files

WMA file extension

Windows Media Audio File

Audio Files

3GP file extension

3GPP Multimedia File

Video Files

7Z file extension

7-Zip Compressed File

Compressed Files