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

ASF file extension

Advanced Systems Format File

Video Files

BAK file extension

Backup File

Backup Files

CER file extension

Internet Security Certificate

Web Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

GAM file extension

Saved Game File

Game Files

GBR file extension

Gerber File

Data Files

ISO file extension

Disc Image File

Disk Image Files

MSI file extension

Windows Installer Package

Misc Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

SQL file extension

Structured Query Language Data File

Database Files

SWF file extension

Shockwave Flash Movie

Video Files

TGA file extension

Targa Graphic

Raster Image Files

TOAST file extension

Toast Disc Image

Disk Image Files

VCD file extension

Virtual CD

Disk Image Files