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

EPUB file extension

Open eBook File

eBook Files

GAM file extension

Saved Game File

Game Files

HTML file extension

Hypertext Markup Language File

Web Files

M4A file extension

MPEG-4 Audio File

Audio Files

MSI file extension

Windows Installer Package

Misc Files

OTF file extension

OpenType Font

Font Files

PART file extension

Partially Downloaded File

Misc Files

PDB file extension

Program Database

Database Files

PIF file extension

Program Information File

Executable Files

PL file extension

Perl Script

Developer Files

PRF file extension

Outlook Profile File

Settings Files

SQL file extension

Structured Query Language Data File

Database Files

TIFF file extension

Tagged Image File Format

Raster Image Files