Use Track Changes to see what changed between versions

Microsoft Word has a built-in comparison tool that shows you exactly what changed between two versions of the same document. Open the newer version first, then go to the Review tab and click Compare. Select Compare again from the dropdown menu, then browse to the older version you want to compare it against.

Word will open a new document showing both versions side by side. The left panel shows the original document, the right panel shows the revised document, and the middle panel highlights every change — deletions in red, additions in blue, and formatting changes in a different color. You can accept or reject each change individually, or accept all changes at once.

This method works best when you're comparing versions of the same document that you or a colleague have edited over time. It's less useful if you're trying to compare two completely different documents or check whether two documents are identical.

Key Takeaways

  • Word's Compare feature shows additions, deletions, and formatting changes in a three-panel view that makes differences impossible to miss.
  • You can accept or reject individual changes, or approve all changes at once before saving the result as a new document.
  • The Combine feature merges multiple edited versions into one document when several people have made changes to separate copies.
  • If you only need to spot-check differences, opening both documents in separate windows and switching between them takes less time than running a full comparison.
  • Word's comparison tool works only with .docx files and older .doc files, not with PDFs or Google Docs files.

Combine multiple edited versions into one document

If three or four people have each edited their own copy of the same document and you need to merge all their changes into one master version, use Combine instead of Compare. Go to the Review tab, click Compare, then select Combine from the dropdown.

Combine works the same way as Compare — it shows you all the changes — but it's designed to handle multiple edited versions at once. You can add one document at a time, and Word will layer all the edits into a single file. This is faster than comparing version A to B, then comparing that result to version C, then to version D.

One limitation: Combine can get confusing if two people made conflicting edits to the same sentence. Word will flag the conflict, but you'll have to decide manually which version to keep. For that reason, Combine works best when different people edited different sections of the document.

Open both documents side by side for quick visual checks

If you just need to spot-check whether two documents are similar or find a specific difference without formally tracking every change, opening them in separate windows is faster. Open the first document, then open the second document in a new Word window. Use your keyboard shortcut to switch between them — Alt+Tab on Windows or Command+Tab on Mac — or position the windows side by side on your screen.

This method takes seconds to set up and doesn't create a new document or require you to accept or reject changes. It's useful when you're comparing a draft to a final version and you only care about a few specific sections, or when you want to copy text from one document into the other without formally merging them.

The downside is that you have to do the work yourself. Word won't highlight what changed or count how many edits were made. You're relying on your own eye to spot differences, which is fine for short documents or small sections but becomes tedious with long files.

Understand what the Compare results actually show

When Word runs a comparison, it shows you changes at the word level, not the character level. If you change "the quick brown fox" to "the fast brown fox," Word highlights the entire word "fast" as new, even though you only changed one letter. This is usually what you want — it makes changes easier to spot — but it means you can't use Word's comparison tool to find tiny typos or single-character differences.

Word also tracks formatting changes separately from text changes. If you made the same sentence bold in one version but not the other, Word will flag that as a change even if the words are identical. You can turn off formatting tracking if it's cluttering your results: in the Compare dialog, uncheck Formatting before you run the comparison.

One more thing to know: Word assumes the document on the left (the one you opened first) is the "original" and the document on the right is the "revised" version. Changes are marked as additions or deletions based on that assumption. If you compare them in the opposite order, additions become deletions and vice versa.

Save the comparison result as a new document

After you've reviewed all the changes and accepted or rejected them, Word gives you the option to save the result. You can save it as a new document with a different name, overwrite one of the originals, or discard the comparison without saving. Most of the time you'll want to save it as a new file — something like "Final_Merged_Version.docx" — so you keep the original documents intact in case you need to go back and check something.

If you accepted all changes, the new document will look like a normal Word file with no tracked changes visible. If you left some changes marked as "pending" without accepting or rejecting them, those will still show up as tracked changes in the saved file, and anyone who opens it can accept or reject them later.

Comparison limitations and when to use other tools

Word's comparison tool only works with Word documents (.docx and .doc files). If one of your documents is a PDF, you'll need to convert it to Word format first, or use a different tool. If you're comparing Google Docs, you can't use Word's Compare feature at all — Google Docs has its own version history tool built in, and you should use that instead.

Word's comparison also doesn't work well with documents that have complex formatting, tables, or images. It can compare them, but the results are often hard to read because Word highlights formatting changes along with text changes. For heavily formatted documents, you might get clearer results by opening both versions side by side and reviewing them manually.

If you need to compare documents that aren't in Word format, or if you need more detailed analysis than Word provides, consider using a dedicated comparison tool like DiffDog, Beyond Compare, or an online diff checker. These tools are built specifically for comparing files and often handle edge cases better than Word does.

Frequently Asked Questions

Can I compare a Word document to a PDF?

Not directly. Word's Compare feature only works with .docx and .doc files. If you need to compare a Word document to a PDF, you can convert the PDF to Word format first using an online converter or Adobe Acrobat, then run the comparison. The conversion may not be perfect, especially if the PDF has complex formatting.

What if I want to compare documents but keep both versions unchanged?

Word's comparison always creates a new document showing the changes. Save that new document with a different name, and your original documents will stay exactly as they are. You can then accept or reject changes in the new document without affecting the originals.

Does Word show who made each change?

Only if the original documents had Track Changes turned on when the edits were made. If someone edited a document without tracking changes, Word won't know who made the change or when. If you want to know who edited what, ask people to turn on Track Changes before they start editing.

Can I compare more than two documents at once?

Not in a single comparison. Use the Combine feature to merge multiple edited versions, which handles more than two documents. You add them one at a time, and Word layers all the changes into one file.

What's the difference between Compare and Combine?

Compare shows you the differences between exactly two documents. Combine is designed to merge multiple edited versions of the same document into one. Use Compare for two versions, and Combine when three or more people have edited separate copies.