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

CBR file extension

Comic Book RAR Archive

Compressed Files

CSS file extension

Cascading Style Sheet

Web Files

EXE file extension

Windows Executable File

Executable Files

JSP file extension

Java Server Page

Web Files

KML file extension

Keyhole Markup Language File

GIS Files

M4A file extension

MPEG-4 Audio File

Audio Files

MDB file extension

Microsoft Access Database

Database Files

MDF file extension

Media Disc Image File

Disk Image Files

MP4 file extension

MPEG-4 Video File

Video Files

MPA file extension

MPEG-2 Audio File

Audio Files

PY file extension

Python Script

Developer Files

RM file extension

Real Media File

Video Files

SAV file extension

Saved Game

Game Files

TORRENT file extension

BitTorrent File

Misc Files

VB file extension

VBScript File

Executable Files