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

ISO file extension

Disc Image File

Disk Image Files

3G2 file extension

3GPP2 Multimedia File

Video Files

FLA file extension

Adobe Flash Animation

Developer Files

IBOOKS file extension

Multi-Touch iBook

Data Files

MPA file extension

MPEG-2 Audio File

Audio Files

CFG file extension

Configuration File

Settings Files

AIF file extension

Audio Interchange File Format

Audio Files

SRT file extension

SubRip Subtitle File

Video Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

BAT file extension

DOS Batch File

Executable Files

GAM file extension

Saved Game File

Game Files

7Z file extension

7-Zip Compressed File

Compressed Files

PHP file extension

PHP Source Code File

Web Files

PKG file extension

Mac OS X Installer Package

Compressed Files

AVI file extension

Audio Video Interleave File

Video Files