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

BAT file extension

DOS Batch File

Executable Files

CBR file extension

Comic Book RAR Archive

Compressed Files

CUE file extension

Cue Sheet File

Disk Image Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

HTM file extension

Hypertext Markup Language File

Web Files

INDD file extension

Adobe InDesign Document

Layout Files

MID file extension

MIDI File

Audio Files

MPA file extension

MPEG-2 Audio File

Audio Files

MSI file extension

Windows Installer Package

Misc Files

PIF file extension

Program Information File

Executable Files

PL file extension

Perl Script

Developer Files

PRF file extension

Outlook Profile File

Settings Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

RTF file extension

Rich Text Format File

Text Files

WSF file extension

Windows Script File

Executable Files