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

BMP file extension

Bitmap Image File

Raster Image Files

CGI file extension

Common Gateway Interface Script

Executable Files

GBR file extension

Gerber File

Data Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

M3U file extension

Media Playlist File

Audio Files

MP3 file extension

MP3 Audio File

Audio Files

MSG file extension

Outlook Mail Message

Text Files

PAGES file extension

Pages Document

Text Files

RSS file extension

Rich Site Summary

Web Files

SH file extension

Bash Shell Script

Developer Files

SQL file extension

Structured Query Language Data File

Database Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

VOB file extension

DVD Video Object File

Video Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

3GP file extension

3GPP Multimedia File

Video Files