DOCX (.docx)
Microsoft Word's Open XML format — the standard for editable document exchange.
- Extension
- .docx
- MIME Type
- application/vnd.openxmlformats-officedocument.wordprocessingml.document
Last updated
What Is a DOCX File?
DOCX is the default format for Microsoft Word documents since Office 2007. It is part of the Office Open XML (OOXML) standard (ISO/IEC 29500). Despite the .docx extension appearing as a single file, it is actually a ZIP archive containing multiple XML files and associated resources.
DOCX Internal Structure
Rename any DOCX to .zip and open it — you will find:
word/document.xml— the main body text as XMLword/styles.xml— paragraph and character style definitionsword/settings.xml— document-level settingsword/theme/theme1.xml— colour and font themeword/media/— folder containing all embedded images[Content_Types].xml— registry of all content types in the package_rels/— relationship files linking document parts
DOCX vs PDF: When to Use Each
| Factor | DOCX | |
|---|---|---|
| Editable | Yes | No (without specialist tools) |
| Consistent rendering | Varies by software | Identical everywhere |
| Best for | Drafts, collaborative editing | Final submission, printing |
| File size | Typically smaller | Larger (embedded fonts + images) |
| Universal opening | Requires Word or compatible app | Requires only a PDF viewer |
Common DOCX Problems
| Problem | Cause | Fix |
|---|---|---|
| "File cannot be opened" | Corruption in document.xml | Re-download or recover from backup |
| Formatting looks wrong | Different Word version or missing fonts | Convert to PDF before sharing |
| Images missing | Broken relationship links | Re-embed images from source |