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

ASP file extension

Active Server Page

Web Files

CSS file extension

Cascading Style Sheet

Web Files

DB file extension

Database File

Database Files

DMP file extension

Windows Memory Dump

System Files

EPUB file extension

Open eBook File

eBook Files

GAM file extension

Saved Game File

Game Files

IFF file extension

Interchange File Format

Audio Files

M file extension

Objective-C Implementation File

Developer Files

MDB file extension

Microsoft Access Database

Database Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

OTF file extension

OpenType Font

Font Files

PL file extension

Perl Script

Developer Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

TARGZ file extension

Compressed Tarball File

Compressed Files

3DM file extension

Rhino 3D Model

3D Image Files