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

AZW file extension

Amazon Kindle eBook File

eBook Files

CLASS file extension

Java Class File

Developer Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

DB file extension

Database File

Database Files

DBF file extension

Database File

Database Files

DDS file extension

DirectDraw Surface

Raster Image Files

DOC file extension

Microsoft Word Document

Text Files

DXF file extension

Drawing Exchange Format File

CAD Files

EPS file extension

Encapsulated PostScript File

Vector Image Files

GPX file extension

GPS Exchange File

GIS Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

M4A file extension

MPEG-4 Audio File

Audio Files

ODT file extension

OpenDocument Text Document

Text Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

WPS file extension

Microsoft Works Word Processor Document

Text Files