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

ACCDB file extension

Access 2007 Database File

Database Files

ASX file extension

Microsoft ASF Redirector File

Video Files

CSR file extension

Certificate Signing Request File

Web Files

DMP file extension

Windows Memory Dump

System Files

EXE file extension

Windows Executable File

Executable Files

MIM file extension

Multi-Purpose Internet Mail Message File

Encoded Files

ODT file extension

OpenDocument Text Document

Text Files

PIF file extension

Program Information File

Executable Files

PKG file extension

Mac OS X Installer Package

Compressed Files

PPS file extension

PowerPoint Slide Show

Data Files

RTF file extension

Rich Text Format File

Text Files

WPD file extension

WordPerfect Document

Text Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files

ZIPX file extension

Extended Zip File

Compressed Files