The problem with Word's Track Changes
Microsoft Word has a built-in Track Changes feature that records every edit as a revision. When it works well, it is powerful — you can accept or reject changes individually and see who made each edit. But it has real limitations.
Track Changes only works if the person editing the document had it switched on before they started editing. If someone sends you a "final" document that was edited with Track Changes off, or if you received a PDF export rather than the source DOCX, you have no revision history to look at. You need to compare the two versions yourself.
Similarly, if someone sends you a document that has been edited compared to a version you already have, you need to do a manual side-by-side comparison — and doing that by eye across a 20-page contract is slow and error-prone.
Comparing two Word documents on FreeDiffChecker
FreeDiffChecker's Document comparison tool extracts the text content from both DOCX files and presents a line-by-line diff. This works with .docx, .doc, .pdf, and .txt files.
To compare two Word documents:
1. Go to freediffchecker.com/document.
2. Upload your original DOCX in the left panel.
3. Upload your revised DOCX in the right panel.
4. Click Compare.
The result shows every paragraph that was added (green), removed (red), or changed. Switch to Side-by-side view to read both versions simultaneously, or use Inline view for a compact single-column summary — useful for copying into an email or a review comment.
No Microsoft Word installation is required. This works on any device with a browser, including iPad and Android tablets.
Comparing Word documents in Google Docs
If you have Google Drive access, Google Docs has a Compare Documents feature built in. Open the newer version of the document in Google Docs, go to Tools > Compare documents, and select the older version from Drive. Google creates a new document showing all differences as tracked changes.
This approach preserves more formatting context than a text-only diff — you can see heading styles, table changes, and formatting differences. The limitation is that both files need to be in Google Drive, and the comparison is only available in the browser version of Google Docs, not in the mobile app.
Comparing PDFs when you do not have the source DOCX
If you only have the PDF versions of two documents — which is common when receiving final contracts or published reports — your options are:
Text extraction diff (best for text-heavy documents): Use FreeDiffChecker's Document tool to extract and compare the text layers of both PDFs. This works well for contracts, reports, and papers that were exported from Word or Google Docs.
Visual diff (best for layout-sensitive documents): Use FreeDiffChecker's Image tool to compare screenshots of the same page from each PDF. Tools like Adobe Acrobat Reader can export individual pages as images. This approach catches layout, formatting, and image changes that text extraction misses.
Adobe Acrobat's Compare Files feature: If you have an Acrobat Pro subscription, it has a built-in PDF comparison that does both text and visual diffing in one pass. It is the most thorough option but requires a paid subscription.
When text extraction is unreliable
Text extraction from PDFs works well for documents that were digitally created (exported from Word, Google Docs, or a typesetting tool). It works poorly or not at all for:
- Scanned documents (the PDF is an image, with no text layer)
- PDFs with complex layouts (multi-column, tables, sidebars) where extraction order may not match reading order
- PDFs created by printing to PDF from a web page, which may extract text in an unexpected order
For scanned documents, run OCR first (Google Drive opens and OCRs PDFs automatically) then re-export before comparing.
Keeping a comparison record
If you need to keep evidence of what changed between two document versions — for a legal record, an audit trail, or a client sign-off — save the diff using FreeDiffChecker's Save feature. A free account lets you store diffs with custom expiry dates and generate a shareable link. The recipient does not need an account to view a shared diff.