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

GBR file extension

Gerber File

Data Files

M4V file extension

iTunes Video File

Video Files

SWF file extension

Shockwave Flash Movie

Video Files

MOBI file extension

Mobipocket eBook

eBook Files

ZIPX file extension

Extended Zip File

Compressed Files

DTD file extension

Document Type Definition File

Developer Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

TEX file extension

LaTeX Source Document

Text Files

VCD file extension

Virtual CD

Disk Image Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

7Z file extension

7-Zip Compressed File

Compressed Files

DMP file extension

Windows Memory Dump

System Files

ASF file extension

Advanced Systems Format File

Video Files

KMZ file extension

Google Earth Placemark File

GIS Files

TIF file extension

Tagged Image File

Raster Image Files