Open both documents side by side

Word has a built-in tool called Compare that shows you exactly what changed between two versions of the same document. But before you use it, you need both files open. The fastest way is to open Word, then open the first document normally. Once it loads, go to File > Open again and open the second document in a new window — Word will open it as a separate instance rather than replacing the first one.

Now you have two Word windows open on your screen. You can arrange them side by side by dragging one window to the left half of your screen and the other to the right, or use Windows' snap feature by dragging a window to the edge. This setup lets you see both documents at once, which is useful if you want to spot differences visually before running the formal comparison.

Use the Compare feature to mark all changes

The Compare tool is in the Review tab. Click the Review tab at the top of Word, then look for the Compare button — it usually sits near the left side of the ribbon. Click it and select Compare from the dropdown menu (not Combine, which does something different).

A dialog box will open asking you to pick an original document and a revised document. The original is usually the older version, and the revised is the newer one. Word will compare them and create a new document that shows every change — deletions appear as strikethrough text in red, additions appear as underlined text in red, and moved text gets marked too. The original and revised documents stay unchanged; Word creates a third document to hold the comparison results.

Read the tracked changes in the new comparison document

Once Word finishes the comparison, a new document opens showing all the differences marked up. The left side of the screen shows a Reviewing Pane that lists every change in order. You can click any change in that pane to jump straight to it in the document. Red strikethrough means text was deleted. Red underline means text was added. If text moved to a different location, Word marks that too.

Scroll through the document or use the Reviewing Pane to see what actually changed. Sometimes the changes are obvious — a sentence added or a word removed. Sometimes they are subtle — a comma added, a space removed, or a number changed. The comparison catches all of it, which is why this tool is useful when you are not sure what someone else modified or when you want to verify that only the changes you expected were made.

Key Takeaways

  • Open both documents in separate Word windows, then use the Review tab and click Compare to create a marked-up version showing all differences.
  • Deletions show as red strikethrough text, and additions show as red underlined text in the comparison document.
  • The Reviewing Pane on the left lists every change in order and lets you jump to each one by clicking.
  • The original and revised documents remain unchanged — Word creates a new document to display the comparison results.
  • You can accept or reject individual changes in the comparison document using the Accept and Reject buttons in the Review tab.

Accept or reject changes one at a time

After you review the comparison, you can decide which changes to keep. The Review tab has Accept and Reject buttons. Click Accept to keep a change and remove the markup, or Reject to remove the change and restore the original text. You can go through the document one change at a time using the navigation arrows next to these buttons, or you can click the dropdown arrow next to Accept and select Accept All Changes to approve everything at once.

Be careful with Accept All Changes — it approves every difference without letting you review each one. If you are not sure about some changes, go through them individually instead. Once you accept or reject all changes, the markup disappears and you are left with a clean document that reflects your decisions.

Save the comparison results or discard them

After you finish accepting and rejecting changes, you have a document with no markup. You can save this as a new file if you want to keep a record of what changed, or you can close it without saving if you only needed to see the differences. If you save it, give it a clear name like "Document_Comparison_Final" so you remember it is the result of a comparison, not an original file.

The original two documents are still separate and unchanged, so you can always run the comparison again if you need to. This is useful if you are working with multiple versions of the same document or if you want to compare different sections to someone else's edits.

Compare documents without opening both first

You do not have to open both documents before running Compare. If you have one document open, you can go to Review > Compare > Compare, and Word will ask you to browse for the other file. Pick the original document first, then the revised document, and Word will handle the rest. This is faster if you are comparing a document you already have open to one sitting in a folder somewhere.

You can also compare documents from File Explorer without opening Word first. Right-click one document, select Open with > Word, then once it opens, use the Compare tool to pick the second file. The result is the same — a new document showing all the differences marked up and ready to review.

Frequently Asked Questions

What is the difference between Compare and Combine?

Compare shows you the differences between two versions of the same document in a new file. Combine merges changes from multiple people who edited the same document separately, preserving each person's edits as tracked changes. Use Compare when you want to see what changed between versions. Use Combine when multiple people sent you edited copies and you want to see all their changes in one place.

Can I compare documents that are very different from each other?

Yes, but the results may be hard to read if the documents are very different. Compare works best when you are comparing two versions of the same document with relatively small changes. If the documents are structured completely differently or have very different content, the comparison may mark almost everything as changed, which is not very useful.

Does Compare work with older Word formats like .doc files?

Yes, Compare works with .doc, .docx, and other Word formats. However, if you are comparing very old .doc files, some formatting may not transfer perfectly. For the most reliable results, save both documents in the current .docx format before comparing them.

What happens if I close the comparison document without saving?

Word will ask if you want to save changes. If you click Don't Save, the comparison document closes and you lose the marked-up version. The original two documents remain unchanged. You can always run the comparison again if you need to see the differences again.

Can I compare more than two documents at once?

The Compare tool only compares two documents at a time. If you need to compare three or more versions, compare the first two, then compare the result to the third document. This takes longer but lets you see all the differences across multiple versions.