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

ASF file extension

Advanced Systems Format File

Video Files

ASP file extension

Active Server Page

Web Files

DNG file extension

Digital Negative Image File

Camera Raw Files

GADGET file extension

Windows Gadget

Executable Files

GBR file extension

Gerber File

Data Files

HTML file extension

Hypertext Markup Language File

Web Files

ISO file extension

Disc Image File

Disk Image Files

KML file extension

Keyhole Markup Language File

GIS Files

PS file extension

PostScript File

Vector Image Files

SYS file extension

Windows System File

System Files

TGA file extension

Targa Graphic

Raster Image Files

VCD file extension

Virtual CD

Disk Image Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

XML file extension

XML File

Data Files

3G2 file extension

3GPP2 Multimedia File

Video Files