The fastest way depends on what changed and how much you trust the tool

If you need to see what changed between two versions of a Word document, you have three main routes: Word's built-in Track Changes feature, a side-by-side manual review, or a dedicated comparison tool. Which one makes sense depends on whether the documents are already in Word, how many changes there are, and whether you want to keep a record of who changed what. The built-in method is fastest for small edits. Manual review works when you need to understand context. Third-party tools matter when you're comparing documents that aren't in Word format or when you need a detailed change log.

Your choice also depends on privacy. Word's Compare feature and manual review keep your documents on your computer. Free web-based comparison tools upload your files to their servers, which is a real risk if the documents contain sensitive information, client data, or personal details. Desktop software like Beyond Compare runs locally and costs money upfront but gives you control over where your files go.

Key Takeaways

  • Word's Compare feature (File > Info > Compare) shows all differences between two documents in a single new document, with changes marked by author and date.
  • If one document already has Track Changes turned on, open it and accept or reject each change one at a time instead of using Compare.
  • Manual side-by-side review in split view works best for short documents or when you need to understand why a change was made, not just what changed.
  • Third-party tools like Diff Checker or Beyond Compare let you compare PDFs, Google Docs, or plain text files, but free web-based tools require uploading your documents to a server.
  • Word's Compare feature does not show formatting changes clearly — use manual review if font, spacing, or style changes matter to your decision.

Using Word's built-in Compare feature

Open Word and go to File > Info > Compare. Click the Compare button (not "Compare and Merge"). Select the original document first, then the revised document. Word creates a new document showing every difference: added text appears in blue, deleted text in red with strikethrough, and moved text in green. Each change is labeled with the author name and timestamp from your Word settings.

This method works well when both files are .docx or .doc format and you want a permanent record of what changed. The comparison document itself is editable — you can accept changes, reject them, or leave them marked. If you need to send the comparison to someone else, they can see exactly what you saw. The downside: if the documents are very long or have many small edits scattered throughout, the comparison can be hard to scan. Word also does not always catch formatting changes like font size or color shifts, so if those matter, you'll need to review manually.

When one document already has Track Changes on

If someone sent you a document with Track Changes already enabled, do not use Compare. Instead, open that document and go through each change one by one using the Review tab. Click Accept or Reject for each change. This approach is slower than Compare if there are hundreds of changes, but it gives you control — you can read the context around each edit, see the comment someone left, and decide whether to keep it.

You can also use the Review tab to turn on Track Changes yourself before making edits, then send the document to someone else to review. This creates a clear audit trail of who changed what and when. If you want to see all changes at once before accepting or rejecting them, use the Reviewing Pane (Review > Reviewing Pane) to list every change in order. This pane shows you a summary count of insertions, deletions, and formatting changes, which helps you spot patterns in what was edited.

Side-by-side manual review in split view

Open both documents in Word and arrange them side by side. Go to View > View Side by Side. This lets you scroll through both documents at the same time and spot differences yourself. Use Find & Replace (Ctrl+H) to search for specific words or phrases in each document if you suspect changes in particular sections.

Manual review takes longer than Compare, but it is useful when you need to understand the reasoning behind changes or when the documents are short. You also avoid uploading documents to any external service, which matters if the files contain sensitive information. The trade-off is that you might miss small changes — a single word swap or a date change can be straightforward to overlook when you're reading two documents at once. For documents longer than 10 pages, use Find to jump to sections you want to verify rather than scrolling through the entire document.

Comparing documents that are not in Word format

If one or both files are PDFs, Google Docs, or plain text, Word's Compare feature will not work. You have two options: convert the files to Word format first, or use a third-party comparison tool.

To convert a PDF to Word, open Word and go to File > Open. Select the PDF file. Word will attempt to convert it to editable text, though the layout may shift. Once it is in Word format, you can use Compare as normal. This works best for PDFs that are mostly text — scanned images or complex layouts often convert poorly. For Google Docs, read the file as a .docx (File > read > Microsoft Word) and then use Compare. If you need to compare two Google Docs without downloading, Google Docs has a built-in version history feature (File > Version history > See version history) that shows who changed what and when, though it does not show a side-by-side diff the way Word does.

Third-party comparison tools and their privacy trade-offs

Tools like Diff Checker, Beyond Compare, and WinMerge let you compare documents in many formats without converting them first. Some are free, some are paid, and some are desktop software you install locally. The choice between them comes down to privacy: web-based tools are convenient but upload your files to someone else's server, while desktop tools keep everything on your computer.

Diff Checker (diffchecker.com) is free and works in your browser. You paste or upload two documents and it shows differences highlighted in color. The downside: you are uploading your documents to their server. If the files contain confidential information, passwords, or personal data, this is a privacy risk. Diff Checker's privacy policy says they store uploads temporarily, but "temporarily" varies by service — it could mean hours or days. For non-sensitive documents, it is fast and requires no installation.

Beyond Compare is desktop software you buy once (around $60) and install on your computer. It compares files locally without uploading anything, which is better for privacy. It handles Word documents, PDFs, plain text, code files, and more. The learning curve is steeper than Word's Compare, but it is powerful if you compare documents regularly. You own the software outright and can use it offline.

WinMerge is free, open-source desktop software for Windows. It compares text files and folders without uploading anything. It is simpler than Beyond Compare but less polished. If you are comparing code or configuration files, it is a solid choice. Since it is open-source, you can inspect the code yourself if you want to verify it is not sending data anywhere.

The privacy question is straightforward: if the tool is web-based and free, assume your documents are being read by the service and possibly used to improve their product. If that is not acceptable, use desktop software or Word's built-in Compare feature, both of which keep your files on your computer.

What to do when the comparison is confusing

Sometimes Word's Compare creates a document that is hard to read — especially if the original and revised documents have very different structures or if there are hundreds of small changes. If that happens, go back to manual side-by-side review. Open both documents, arrange them side by side, and use Find (Ctrl+F) to jump to specific sections you want to check. You can also turn on formatting marks (Ctrl+*) to see invisible characters like spaces and line breaks that might explain why Word flagged something as changed.

Another option: ask the person who made the changes to tell you what they changed. This sounds obvious, but it saves time. If you are comparing versions from different people or different dates, a quick email asking "What did you change in the budget section?" is often faster than hunting through a 50-page comparison document. If you need to keep a permanent record of the comparison, export the Compare result as a PDF (File > Save As > PDF) so it cannot be accidentally edited later. Name it clearly with the date and version numbers — for example, "Contract_v1_vs_v2_Jan15.pdf".

Frequently Asked Questions

Does Word's Compare feature work with Google Docs?

Not directly. read the Google Doc as a .docx file first (File > read > Microsoft Word), then use Word's Compare feature. If you want to compare two Google Docs without downloading, use Google Docs' built-in version history instead (File > Version history > See version history), though it does not show a side-by-side comparison.

Can I compare two Word documents if one is on my computer and one is in OneDrive?

Yes. Open the OneDrive document in Word, save a copy to your computer, then use Compare. Alternatively, if both documents are in OneDrive, you can read one and compare locally. Word's Compare feature works with any two .docx or .doc files regardless of where they are stored.

What if the comparison shows changes I did not make?

This usually happens because Word is detecting formatting changes — line breaks, spacing, or style adjustments — that are not visible at first glance. Open both documents side by side and look at the formatting (View > Show Formatting Marks) to see where the differences really are. If changes appear that you genuinely did not make, someone else edited the document, or the file was corrupted and repaired by Word.

Is it safe to use free online comparison tools with confidential documents?

No. Free web-based tools upload your documents to their servers, and you have no way to verify what happens to them afterward. For confidential, sensitive, or personal information, use Word's Compare feature or desktop software like Beyond Compare that runs locally on your computer.

Can I compare documents that are different file types, like Word and PDF?

Not with Word's Compare feature. Convert the PDF to Word format first (File > Open, select the PDF), then use Compare. Be aware that PDF conversion often changes the layout, so the comparison may show formatting differences that are just artifacts of the conversion, not real changes to the content.