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

COM file extension

DOS Command File

Executable Files

CSR file extension

Certificate Signing Request File

Web Files

DWG file extension

AutoCAD Drawing Database File

CAD Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

FON file extension

Generic Font File

Font Files

H file extension

C/C++/Objective-C Header File

Developer Files

INDD file extension

Adobe InDesign Document

Layout Files

MPA file extension

MPEG-2 Audio File

Audio Files

MSI file extension

Windows Installer Package

Misc Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

PS file extension

PostScript File

Vector Image Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

RPM file extension

Red Hat Package Manager File

Compressed Files

WMA file extension

Windows Media Audio File

Audio Files

ZIP file extension

Zipped File

Compressed Files