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

AZW file extension

Amazon Kindle eBook File

eBook Files

BAK file extension

Backup File

Backup Files

BAT file extension

DOS Batch File

Executable Files

CFG file extension

Configuration File

Settings Files

DEB file extension

Debian Software Package

Compressed Files

DLL file extension

Dynamic Link Library

System Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

FLA file extension

Adobe Flash Animation

Developer Files

GED file extension

GEDCOM Genealogy Data File

Data Files

JPG file extension

JPEG Image

Raster Image Files

MPG file extension

MPEG Video File

Video Files

PNG file extension

Portable Network Graphic

Raster Image Files

ROM file extension

N64 Game ROM File

Game Files

WMV file extension

Windows Media Video File

Video Files