The fastest way to spot what changed between two documents

Word has a built-in tool called Track Changes that shows you exactly what was added, deleted, or moved between two versions of a document. If you have an older version and a newer version sitting on your computer, you can open both side by side or use Word's compare feature to highlight every difference in red, blue, and strikethrough text. The process takes about two minutes and requires no special software beyond Word itself.

The method you choose depends on whether you already have both documents open, whether you want to see changes marked inside one document, or whether you want to view them side by side. Word offers three main paths: opening documents side by side, using the built-in Compare tool, or reviewing Track Changes if one document already has them marked.

Key Takeaways

  • Word's Compare feature automatically marks all differences between two documents in a new third document, using color-coded insertions, deletions, and moves.
  • Opening two documents side by side lets you scan both at once but does not automatically highlight what changed — you spot differences yourself.
  • Track Changes must be turned on before editing to record who made changes and when; comparing two finished documents does not retroactively show who changed what.
  • The Compare tool works on any two Word documents regardless of whether changes were tracked during editing.

Using the Compare feature to mark all differences automatically

Open the first document (the original version). Go to the Review tab at the top of the ribbon. Click Compare, then select Compare again from the dropdown menu. A dialog box opens asking you to choose the document you want to compare it to — select the second document (the revised version). Word creates a new document showing every change marked in color.

In the new document, deletions appear as strikethrough text in red, additions appear in blue, and moved text shows as both a deletion and insertion. The left panel shows a summary of all changes grouped by type. You can click any change to jump to it in the document. This method is the fastest way to see everything that differs, and it does not alter either of your original documents.

If the documents are very long or have many small changes, the marked-up version can look cluttered. You can hide certain types of changes by unchecking boxes in the Review tab — for example, uncheck Insertions and Deletions to see only moved text, or uncheck Formatting to ignore font or color changes and focus only on content.

Opening two documents side by side to scan both at once

Open both documents. Go to the View tab and click View Side by Side. The two documents appear in equal-width panes on your screen, one on the left and one on the right. When you scroll in one document, the other scrolls at the same pace, so you can compare the same section of each file at the same time.

This method does not automatically highlight changes — you read through both versions and spot differences yourself. It works well when you want to understand the context of a change or when the documents are short enough to scan quickly. It is also useful when you want to copy text from one document into the other without creating a marked-up third file.

To stop viewing side by side, go back to the View tab and click View Side by Side again to turn it off. Both documents remain open in separate windows.

Understanding Track Changes and when it applies

Track Changes is a feature you turn on before editing a document. Once it is on, every insertion, deletion, and format change is recorded with the editor's name and timestamp. If someone edited a document with Track Changes on, you can see exactly what they changed by reviewing the marked-up version.

However, if you have two finished documents and neither one has Track Changes marked in it, using the Compare feature is the only way to see what differs. Track Changes does not work retroactively — it cannot tell you what changed in a document that was edited without the feature turned on. If you receive a document and want to know what the previous version looked like, Compare is your tool, not Track Changes.

If a document does have Track Changes marked, you can accept or reject each change one at a time. Go to the Review tab, and use Accept or Reject buttons to approve or undo each marked change. You can also click Accept All to approve every change at once, which removes all the markup and finalizes the document.

Reviewing the marked-up document and accepting or rejecting changes

After you use Compare, the new document shows all differences. The Review tab displays buttons for Accept and Reject. Click Accept to keep a change and remove its markup, or click Reject to undo it and remove the markup. You can move through changes one at a time using the navigation arrows, or click Accept All to approve every difference at once.

Before accepting all changes, scroll through the document to make sure the marked differences are what you expected. Sometimes formatting changes or line breaks create false positives — Word may mark a space or indent as a change even though the content is identical. Reviewing manually takes longer but catches these false alarms.

Once you accept or reject all changes, the markup disappears and you have a clean document. Save it with a new name if you want to keep the marked-up version for your records, or overwrite the original if you are confident in the changes.

Comparing documents when one has Track Changes already marked

If someone sent you a document with Track Changes already turned on, you do not need to use the Compare feature. Instead, open the document and go to the Review tab. The marked changes appear in the document with the editor's name and the date of the change. You can accept or reject them individually or all at once using the buttons in the Review tab.

If you want to see what the document looked like before any changes, click Display for Review (in the Review tab) and select Original from the dropdown. The document shows the version before edits. Switch back to Final to see the version with all changes accepted. This is useful when you want to understand what was in the document before someone edited it.

When Compare does not work as expected

The Compare feature works best when both documents have the same basic structure — the same headings, paragraphs, and sections in roughly the same order. If one document is a complete rewrite or has been reorganized heavily, Word may mark almost every line as changed, making the output hard to read.

If the documents are in different formats (one is a .docx file and one is a .doc file, for example), Word converts them to the same format before comparing. This usually works without problems, but very old .doc files or documents with complex formatting may not convert perfectly. Save both documents as .docx before comparing if you run into issues.

If you compare the same document to itself by mistake, Word will show no changes. If you compare two documents that are identical, the Compare result will be blank. These are not errors — they are correct results.

Frequently Asked Questions

Can I compare documents if one is in Google Docs and one is in Word?

No, Word's Compare feature only works with Word documents. read the Google Doc as a .docx file first, then use Compare. To read, open the Google Doc, click File, then read, and select Microsoft Word (.docx). Once both files are in Word format, you can compare them.

Does Compare show me who made each change?

No. Compare shows what changed, but not who changed it or when. If you need to know who edited what, the original document must have had Track Changes turned on during editing. Compare only works on finished documents and cannot identify the editor.

What if I compare the wrong two documents by mistake?

Word creates a new document with the comparison results, so your original documents are not affected. Close the marked-up document without saving it, and your originals remain unchanged. You can then open the correct documents and compare them again.

Can I undo accepting all changes at once?

Yes, use Ctrl+Z (or Cmd+Z on Mac) when ready after clicking Accept All. This undoes the acceptance and brings back all the markup. If you have already saved the document, you will need to close it without saving and reopen the marked-up version.

Does Compare work on documents with images or tables?

Yes, but Compare treats images and tables as single objects. If an image or table changed, Word marks the entire object as changed rather than showing what specifically changed inside it. For detailed changes to tables, reviewing side by side is often clearer than using Compare.