DOCX file: what it is and how to open one

What is a DOCX file?

A DOCX file is a word-processing document in the Office Open XML format, the default file type for Microsoft Word since 2007. Other editors, including browser-based ones, can open and save it too.

DOCX vs DOC

DOC is Word’s older binary format, used up to Word 2003. DOCX replaced it with an open, XML-based format that is smaller, less prone to corruption and easier for other software to read. If you have the choice, save as DOCX.

What is inside a DOCX file

The DOCX file format is a ZIP archive of XML files: one for the text and structure, others for styles, images, comments and settings. That is why renaming a .docx file to .zip lets you look inside, and why so many tools can read it.

How to open a DOCX file

Microsoft Word opens it natively, and so do most word processors. You can also open DOCX without Word in a browser-based editor: Arkenso Docs opens a .docx file straight into the editor, lets a team work on it together, and exports it back to Word whenever you need the file.

DOCX vs PDF

A DOCX is meant to be edited; a PDF is meant to look the same everywhere. Send a DOCX when the reader should make changes or comments, and a PDF when the layout must not move, such as a signed contract or a final report.

Last reviewed 2026-11-01.

Related terms

  • XLSX file — An XLSX file is a spreadsheet in the Office Open XML format, the default file type for Microsoft Excel since 2007.
  • PPTX file — A PPTX file is a presentation in the Office Open XML format, the default file type for Microsoft PowerPoint since 2007.
  • Real-time collaboration — Real-time collaboration means several people editing the same document, spreadsheet or presentation at the same time, each seeing the others’ changes and cursors appear within moments.

All glossary terms →