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

DB file extension

Database File

Database Files

DBF file extension

Database File

Database Files

DLL file extension

Dynamic Link Library

System Files

DMG file extension

Mac OS X Disk Image

Disk Image Files

DMP file extension

Windows Memory Dump

System Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

GPX file extension

GPS Exchange File

GIS Files

HTML file extension

Hypertext Markup Language File

Web Files

ICO file extension

Icon File

System Files

OTF file extension

OpenType Font

Font Files

PNG file extension

Portable Network Graphic

Raster Image Files

PPT file extension

PowerPoint Presentation

Data Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

SLN file extension

Visual Studio Solution File

Developer Files