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

AZW file extension

Amazon Kindle eBook File

eBook Files

CS file extension

Visual C# Source Code File

Developer Files

DB file extension

Database File

Database Files

GADGET file extension

Windows Gadget

Executable Files

GZ file extension

Gnu Zipped Archive

Compressed Files

IBOOKS file extension

Multi-Touch iBook

Data Files

IFF file extension

Interchange File Format

Audio Files

LUA file extension

Lua Source File

Developer Files

MAX file extension

3ds Max Scene File

3D Image Files

MOBI file extension

Mobipocket eBook

eBook Files

MOV file extension

Apple QuickTime Movie

Video Files

TOAST file extension

Toast Disc Image

Disk Image Files

UUE file extension

Uuencoded File

Encoded Files

VB file extension

VBScript File

Executable Files

3GP file extension

3GPP Multimedia File

Video Files