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

CAB file extension

Windows Cabinet File

System Files

CBR file extension

Comic Book RAR Archive

Compressed Files

CS file extension

Visual C# Source Code File

Developer Files

DB file extension

Database File

Database Files

DMP file extension

Windows Memory Dump

System Files

FLV file extension

Flash Video File

Video Files

GADGET file extension

Windows Gadget

Executable Files

MPG file extension

MPEG Video File

Video Files

MSG file extension

Outlook Mail Message

Text Files

PDF file extension

Portable Document Format File

Layout Files

PPT file extension

PowerPoint Presentation

Data Files

PRF file extension

Outlook Profile File

Settings Files

WPS file extension

Microsoft Works Word Processor Document

Text Files

XCODEPROJ file extension

Xcode Project

Developer Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files