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

ASF file extension

Advanced Systems Format File

Video Files

BMP file extension

Bitmap Image File

Raster Image Files

CPP file extension

C++ Source Code File

Developer Files

CUR file extension

Windows Cursor

System Files

DBF file extension

Database File

Database Files

DMP file extension

Windows Memory Dump

System Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

DTD file extension

Document Type Definition File

Developer Files

EPUB file extension

Open eBook File

eBook Files

FLA file extension

Adobe Flash Animation

Developer Files

KMZ file extension

Google Earth Placemark File

GIS Files

PAGES file extension

Pages Document

Text Files

PCT file extension

Picture File

Layout Files

PDB file extension

Program Database

Database Files

VCXPROJ file extension

Visual C++ Project

Developer Files