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

APK file extension

Android Package File

Executable Files

AZW file extension

Amazon Kindle eBook File

eBook Files

CLASS file extension

Java Class File

Developer Files

CUE file extension

Cue Sheet File

Disk Image Files

DEM file extension

Video Game Demo File

Game Files

DNG file extension

Digital Negative Image File

Camera Raw Files

JAVA file extension

Java Source Code File

Developer Files

MDB file extension

Microsoft Access Database

Database Files

PPS file extension

PowerPoint Slide Show

Data Files

PPT file extension

PowerPoint Presentation

Data Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

VCD file extension

Virtual CD

Disk Image Files

XCODEPROJ file extension

Xcode Project

Developer Files

ZIPX file extension

Extended Zip File

Compressed Files