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

C file extension

C/C++ Source Code File

Developer Files

CLASS file extension

Java Class File

Developer Files

DRV file extension

Device Driver

System Files

GADGET file extension

Windows Gadget

Executable Files

KEY file extension

Keynote Presentation

Data Files

M4V file extension

iTunes Video File

Video Files

MID file extension

MIDI File

Audio Files

MPG file extension

MPEG Video File

Video Files

RA file extension

Real Audio File

Audio Files

RTF file extension

Rich Text Format File

Text Files

SQL file extension

Structured Query Language Data File

Database Files

TEX file extension

LaTeX Source Document

Text Files

TORRENT file extension

BitTorrent File

Misc Files

TTF file extension

TrueType Font

Font Files

ZIPX file extension

Extended Zip File

Compressed Files