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

FON file extension

Generic Font File

Font Files

GPX file extension

GPS Exchange File

GIS Files

IFF file extension

Interchange File Format

Audio Files

JS file extension

JavaScript File

Web Files

MOBI file extension

Mobipocket eBook

eBook Files

ODT file extension

OpenDocument Text Document

Text Files

PDB file extension

Program Database

Database Files

PDF file extension

Portable Document Format File

Layout Files

PHP file extension

PHP Source Code File

Web Files

PPT file extension

PowerPoint Presentation

Data Files

PY file extension

Python Script

Developer Files

TORRENT file extension

BitTorrent File

Misc Files

UUE file extension

Uuencoded File

Encoded Files

ZIP file extension

Zipped File

Compressed Files

3DM file extension

Rhino 3D Model

3D Image Files