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

CFG file extension

Configuration File

Settings Files

3DS file extension

3D Studio Scene

3D Image Files

JAVA file extension

Java Source Code File

Developer Files

DBF file extension

Database File

Database Files

ICS file extension

iCalendar File

Misc Files

MSI file extension

Windows Installer Package

Misc Files

PRF file extension

Outlook Profile File

Settings Files

AI file extension

Adobe Illustrator File

Vector Image Files

DNG file extension

Digital Negative Image File

Camera Raw Files

DMG file extension

Mac OS X Disk Image

Disk Image Files

7Z file extension

7-Zip Compressed File

Compressed Files

WAV file extension

WAVE Audio File

Audio Files

PS file extension

PostScript File

Vector Image Files

CLASS file extension

Java Class File

Developer Files

PDB file extension

Program Database

Database Files