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

ACCDB file extension

Access 2007 Database File

Database Files

DAT file extension

Data File

Data Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

GED file extension

GEDCOM Genealogy Data File

Data Files

JSP file extension

Java Server Page

Web Files

MAX file extension

3ds Max Scene File

3D Image Files

MID file extension

MIDI File

Audio Files

MOBI file extension

Mobipocket eBook

eBook Files

NES file extension

Nintendo (NES) ROM File

Game Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

PSD file extension

Adobe Photoshop Document

Raster Image Files

ROM file extension

N64 Game ROM File

Game Files

VCF file extension

vCard File

Data Files

WPS file extension

Microsoft Works Word Processor Document

Text Files