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

EPS file extension

Encapsulated PostScript File

Vector Image Files

IBOOKS file extension

Multi-Touch iBook

Data Files

ICO file extension

Icon File

System Files

LUA file extension

Lua Source File

Developer Files

M file extension

Objective-C Implementation File

Developer Files

MPG file extension

MPEG Video File

Video Files

NES file extension

Nintendo (NES) ROM File

Game Files

PHP file extension

PHP Source Code File

Web Files

PIF file extension

Program Information File

Executable Files

PPT file extension

PowerPoint Presentation

Data Files

RSS file extension

Rich Site Summary

Web Files

SQL file extension

Structured Query Language Data File

Database Files

TIF file extension

Tagged Image File

Raster Image Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files

ZIPX file extension

Extended Zip File

Compressed Files