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

ASX file extension

Microsoft ASF Redirector File

Video Files

CER file extension

Internet Security Certificate

Web Files

CPP file extension

C++ Source Code File

Developer Files

DXF file extension

Drawing Exchange Format File

CAD Files

GED file extension

GEDCOM Genealogy Data File

Data Files

HTML file extension

Hypertext Markup Language File

Web Files

JAR file extension

Java Archive File

Executable Files

LUA file extension

Lua Source File

Developer Files

PS file extension

PostScript File

Vector Image Files

VOB file extension

DVD Video Object File

Video Files

WAV file extension

WAVE Audio File

Audio Files

WPD file extension

WordPerfect Document

Text Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files

XML file extension

XML File

Data Files