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

CGI file extension

Common Gateway Interface Script

Executable Files

DBF file extension

Database File

Database Files

DXF file extension

Drawing Exchange Format File

CAD Files

GZ file extension

Gnu Zipped Archive

Compressed Files

M file extension

Objective-C Implementation File

Developer Files

NES file extension

Nintendo (NES) ROM File

Game Files

PDF file extension

Portable Document Format File

Layout Files

PLUGIN file extension

Mac OS X Plug-in

Plugin Files

PNG file extension

Portable Network Graphic

Raster Image Files

RSS file extension

Rich Site Summary

Web Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

TARGZ file extension

Compressed Tarball File

Compressed Files

VCXPROJ file extension

Visual C++ Project

Developer Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files