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

ASP file extension

Active Server Page

Web Files

COM file extension

DOS Command File

Executable Files

DNG file extension

Digital Negative Image File

Camera Raw Files

DOC file extension

Microsoft Word Document

Text Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

GADGET file extension

Windows Gadget

Executable Files

ICS file extension

iCalendar File

Misc Files

MOBI file extension

Mobipocket eBook

eBook Files

MP3 file extension

MP3 Audio File

Audio Files

MPG file extension

MPEG Video File

Video Files

MSI file extension

Windows Installer Package

Misc Files

PKG file extension

Mac OS X Installer Package

Compressed Files

VCF file extension

vCard File

Data Files

3DM file extension

Rhino 3D Model

3D Image Files