What is a .docx file?
Microsoft Word Open XML Document · Document · Microsoft · 2007
DOCX is the modern Word document format. It is really a zip archive of XML files, which makes it compact and open, and it is the default for letters, reports and essays across Word, Google Docs and LibreOffice.
What is a .docx file used for?
Since Word 2007, DOCX replaced the old binary DOC. Rename a DOCX to .zip and you can see the XML and images inside, which is why it is smaller and more resilient than the old format.
It stores formatted text, styles, tables, images and tracked changes. Google Docs, LibreOffice and Apple Pages all read and write it.
The older .doc format is the binary predecessor. Most apps still open it, but new documents should be DOCX.
Because a DOCX is a ZIP underneath, it shares the same first bytes as XLSX and PPTX, so a file identifier sees a ZIP archive and relies on the extension to tell which Office file it is. It also means a corrupted DOCX can report as a broken archive, and opening it in LibreOffice or Google Docs, which are more forgiving, often recovers it.
How to open a .docx file
The .docx format opens in the following apps, grouped by operating system. If one app does not work, try another from the same list. For a step-by-step walkthrough, see how to open a .docx file.
Windows
- Microsoft Word
- LibreOffice
- Google Docs
- WordPad
macOS
- Word
- Pages
- LibreOffice
- Google Docs
Linux
- LibreOffice
- OnlyOffice
- Google Docs
Web
- Google Docs
- Office on the web
How to convert a .docx file
You can convert a .docx file to PDF, TXT, ODT, RTF using a conversion tool or the export menu of an app that opens it.
.docx file signature (magic bytes)
Programs recognise a .docx file by the bytes at the start of the file, not by its name. These are the signatures for DOCX. For a full breakdown, see the DOCX file signature page.
| Hex signature | Offset | Note |
|---|---|---|
| 50 4B 03 04 | 0 | ZIP header (Office Open XML) |
See the full magic-numbers reference for every format.
Frequently asked questions
What is a .docx file?
DOCX is the modern Word document format. It is really a zip archive of XML files, which makes it compact and open, and it is the default for letters, reports and essays across Word, Google Docs and LibreOffice.
Why won't my DOCX file open?
Common causes: a very old Word (before 2007) needs Microsoft's free Compatibility Pack; the file was renamed from another type; or the download finished incomplete. Since a DOCX is a ZIP underneath, a corrupted one can look like a broken archive, so try opening it in LibreOffice or Google Docs, which are more forgiving.
How do I open a DOCX without Word?
Use the free LibreOffice, Google Docs or Apple Pages. All open and edit DOCX files faithfully.
What is the difference between DOC and DOCX?
DOC is the older binary Word format. DOCX, introduced in 2007, is a smaller, open, zip-based XML format and is the current standard.
Comparisons
Related formats
Sources
Details on this page were checked against authoritative references: