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

CAB file extension

Windows Cabinet File

System Files

CUE file extension

Cue Sheet File

Disk Image Files

DB file extension

Database File

Database Files

DEB file extension

Debian Software Package

Compressed Files

DOC file extension

Microsoft Word Document

Text Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

MID file extension

MIDI File

Audio Files

MP3 file extension

MP3 Audio File

Audio Files

OTF file extension

OpenType Font

Font Files

ROM file extension

N64 Game ROM File

Game Files

WAV file extension

WAVE Audio File

Audio Files

WMA file extension

Windows Media Audio File

Audio Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

3DM file extension

Rhino 3D Model

3D Image Files