What is the default file extension of a Microsoft Word document?

The default file extension for a Microsoft Word document is .docx. This extension was introduced with Word 2007 as part of the Office Open XML format, offering improved file recovery and smaller file sizes compared to older formats.

• .txt is the extension for plain text files, which contain no formatting.
• .xls is the default file extension for Microsoft Excel spreadsheets in older versions (pre-2007). The current default is .xlsx.
• .pptx is the default file extension for Microsoft PowerPoint presentations.

Knowing file extensions helps identify the type of document and the program required to open it.