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

CFM file extension

ColdFusion Markup File

Web Files

CRX file extension

Chrome Extension

Plugin Files

CSR file extension

Certificate Signing Request File

Web Files

CSV file extension

Comma Separated Values File

Data Files

DMP file extension

Windows Memory Dump

System Files

EPUB file extension

Open eBook File

eBook Files

EXE file extension

Windows Executable File

Executable Files

GADGET file extension

Windows Gadget

Executable Files

IBOOKS file extension

Multi-Touch iBook

Data Files

IFF file extension

Interchange File Format

Audio Files

JSP file extension

Java Server Page

Web Files

KML file extension

Keyhole Markup Language File

GIS Files

SLN file extension

Visual Studio Solution File

Developer Files

TIFF file extension

Tagged Image File Format

Raster Image Files

XLR file extension

Works Spreadsheet

Spreadsheet Files