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

AIF file extension

Audio Interchange File Format

Audio Files

DB file extension

Database File

Database Files

FLV file extension

Flash Video File

Video Files

IBOOKS file extension

Multi-Touch iBook

Data Files

INI file extension

Windows Initialization File

Settings Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

PL file extension

Perl Script

Developer Files

PS file extension

PostScript File

Vector Image Files

RA file extension

Real Audio File

Audio Files

RSS file extension

Rich Site Summary

Web Files

SQL file extension

Structured Query Language Data File

Database Files

SYS file extension

Windows System File

System Files

TOAST file extension

Toast Disc Image

Disk Image Files

VCXPROJ file extension

Visual C++ Project

Developer Files

YUV file extension

YUV Encoded Image File

Raster Image Files