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

OBJ file extension

Wavefront 3D Object File

3D Image Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

M4A file extension

MPEG-4 Audio File

Audio Files

VOB file extension

DVD Video Object File

Video Files

PPS file extension

PowerPoint Slide Show

Data Files

DESKTHEMEPACK file extension

Windows 8 Desktop Theme Pack File

System Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

YUV file extension

YUV Encoded Image File

Raster Image Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

ICS file extension

iCalendar File

Misc Files

TGA file extension

Targa Graphic

Raster Image Files

AZW file extension

Amazon Kindle eBook File

eBook Files

WMA file extension

Windows Media Audio File

Audio Files

7Z file extension

7-Zip Compressed File

Compressed Files

GIF file extension

Graphical Interchange Format File

Raster Image Files