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

ACCDB file extension

Access 2007 Database File

Database Files

APK file extension

Android Package File

Executable Files

CBR file extension

Comic Book RAR Archive

Compressed Files

CS file extension

Visual C# Source Code File

Developer Files

CUR file extension

Windows Cursor

System Files

DDS file extension

DirectDraw Surface

Raster Image Files

DLL file extension

Dynamic Link Library

System Files

FLA file extension

Adobe Flash Animation

Developer Files

IFF file extension

Interchange File Format

Audio Files

KMZ file extension

Google Earth Placemark File

GIS Files

ODT file extension

OpenDocument Text Document

Text Files

PDF file extension

Portable Document Format File

Layout Files

PPT file extension

PowerPoint Presentation

Data Files

SAV file extension

Saved Game

Game Files

TOAST file extension

Toast Disc Image

Disk Image Files