Upload your original .docx file on the left and the updated version on the right, then click Find Differences. The tool uses mammoth.js to extract plain text from both documents and shows every changed paragraph in color-coded diff output. Formatting changes (bold, font size, color) are not compared - only text content.
How to use this tool
Drop each .docx file into its panel and click "Find Differences." The tool loads mammoth.js on demand, extracts the plain text from both documents, and runs a paragraph-level diff. Additions appear in green, removals in red. Empty paragraphs are filtered to keep the output readable.
How document text extraction works
This tool uses mammoth.js to read .docx files. Mammoth converts the XML structure of a Word document into plain text, preserving the text content of each paragraph. The extracted text from both documents is then compared line by line using an LCS diff algorithm - the same algorithm used by Git's diff command.
Limitations
- Only .docx format is supported. Older .doc (Word 97-2003) files are not supported. Convert them to .docx in Word or LibreOffice first.
- Formatting is not compared. Bold, italic, font changes, colors, and track changes are not part of the text extraction. For formatting comparison, use Word's built-in Compare Documents feature (Review → Compare).
- Tables and complex layouts. Text in tables is extracted but may not match its visual position in the document. The diff compares text content, not table structure.
Use cases
Contract and agreement redlines
When a Word document is revised and returned, upload both versions to see every paragraph that changed. A single sentence edit or added clause will show clearly in the diff, without having to read both documents word for word.
Academic and editorial revisions
Compare two drafts of an essay, report, or manuscript to confirm which sections changed between revisions. Useful for writers, editors, and academic supervisors reviewing annotated drafts.
Policy and procedure document updates
When an organization updates an internal policy or procedure document, comparing the old and new versions immediately shows which sections were added, removed, or reworded - producing a clear audit record of what changed.
FAQs
Does this compare .doc files?
No. Only .docx (Office Open XML) is supported. Convert older .doc files to .docx in Microsoft Word (File → Save As → .docx) or LibreOffice Writer.
Are formatting changes shown?
No. Only plain text content is compared. For formatting and track changes, use Word's built-in Compare Documents feature under the Review tab.
Is my document private?
Yes. Everything runs in your browser using mammoth.js. No file content is sent to any server.