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

AZW file extension

Amazon Kindle eBook File

eBook Files

BAK file extension

Backup File

Backup Files

BMP file extension

Bitmap Image File

Raster Image Files

DMP file extension

Windows Memory Dump

System Files

GADGET file extension

Windows Gadget

Executable Files

HTML file extension

Hypertext Markup Language File

Web Files

IFF file extension

Interchange File Format

Audio Files

JAVA file extension

Java Source Code File

Developer Files

KMZ file extension

Google Earth Placemark File

GIS Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

PRF file extension

Outlook Profile File

Settings Files

VCD file extension

Virtual CD

Disk Image Files

ZIP file extension

Zipped File

Compressed Files