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

DB file extension

Database File

Database Files

DBF file extension

Database File

Database Files

DDS file extension

DirectDraw Surface

Raster Image Files

GADGET file extension

Windows Gadget

Executable Files

GAM file extension

Saved Game File

Game Files

M4A file extension

MPEG-4 Audio File

Audio Files

PIF file extension

Program Information File

Executable Files

TARGZ file extension

Compressed Tarball File

Compressed Files

TIF file extension

Tagged Image File

Raster Image Files

TTF file extension

TrueType Font

Font Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files

3DM file extension

Rhino 3D Model

3D Image Files