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

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

CPL file extension

Windows Control Panel Item

System Files

MSI file extension

Windows Installer Package

Misc Files

KML file extension

Keyhole Markup Language File

GIS Files

7Z file extension

7-Zip Compressed File

Compressed Files

DBF file extension

Database File

Database Files

RPM file extension

Red Hat Package Manager File

Compressed Files

SRT file extension

SubRip Subtitle File

Video Files

EPUB file extension

Open eBook File

eBook Files

JAVA file extension

Java Source Code File

Developer Files

XLS file extension

Excel Spreadsheet

Spreadsheet Files

CSR file extension

Certificate Signing Request File

Web Files

3DM file extension

Rhino 3D Model

3D Image Files

WSF file extension

Windows Script File

Executable Files