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

BAT file extension

DOS Batch File

Executable Files

CBR file extension

Comic Book RAR Archive

Compressed Files

CFM file extension

ColdFusion Markup File

Web Files

CPP file extension

C++ Source Code File

Developer Files

CUR file extension

Windows Cursor

System Files

DEB file extension

Debian Software Package

Compressed Files

M4V file extension

iTunes Video File

Video Files

NES file extension

Nintendo (NES) ROM File

Game Files

ODT file extension

OpenDocument Text Document

Text Files

RTF file extension

Rich Text Format File

Text Files

SAV file extension

Saved Game

Game Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

THM file extension

Thumbnail Image File

Raster Image Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files