Compare Documents in Word and Create a Redline

To compare two versions of a document in Microsoft Word, open Word and choose Review > Compare > Compare, select the original and revised files, then choose OK. Word creates a new document showing the differences as tracked changes, so you can review, accept, or reject them without changing either source file. Have both versions saved and available before you begin.

What You’ll Need

A desktop version of Microsoft Word, preferably Microsoft 365 or a recent standalone edition. The Compare command is available in Word for Windows and Word for Mac, though labels and dialog layouts may vary slightly by release.
The two documents you want to check: the earlier version (the original) and the later version (the revised copy). Word can compare saved Word files such as .docx and .doc. If a file is in PDF or another format, convert it to an editable Word document first and check the conversion for layout changes.
Access to both files, either on your computer or in a location Word can browse to, such as OneDrive. If either document is protected or password-encrypted, you may need permission or the password to open and compare it.

Step-by-Step

Identify the earlier and later versions. Decide which file is the baseline and which contains the newer edits. The original is the document Word treats as the starting point; the revised document is the version whose changes Word identifies. File names like Report_original.docx and Report_revised.docx can help prevent a swap. If you are unsure, open both files and check their dates or contents before comparing.
Save clean copies and close unnecessary documents. Save any work in progress, and consider making backup copies of the two source files. Word normally leaves the source documents unchanged and puts the comparison in a third document, but backups make it easier to recover if you later edit or overwrite a file by mistake. You do not have to close the source documents, but doing so can make file selection less confusing.
Open the Compare command. In Word for Microsoft 365 on Windows, select the Review tab, open the Compare drop-down, and choose Compare. In some releases, the command appears as Compare Documents. On Word for Mac, use Review > Compare > Compare Documents or the equivalent Compare command shown in your version. If the button is not visible, maximize the Word window or check the Review tab’s overflow menu.
Choose the original document. In the Compare Documents dialog, use the file or folder button beside Original document to browse to the earlier file. Select it and confirm the choice. Check the displayed file name rather than relying only on the folder location, especially if several versions have similar names.
Choose the revised document. Use the control beside Revised document to select the later file. Confirm that the original and revised selections are not reversed. The direction matters: it determines which text Word treats as existing and which it displays as inserted, deleted, or changed. The comparison still identifies differences if the versions are reversed, but the markup may be harder to interpret.
Set the comparison details. Enter a label in Label changes with, such as Reviewer or Editorial update. This label helps identify the comparison’s markup; it is not a substitute for checking who actually made the edits. Select More or expand the options if you need to choose what Word compares, such as text, formatting, comments, or case changes. For a typical redline, leave the relevant text and formatting options selected. If you only want wording differences, turn off formatting comparison to avoid a large number of layout marks.
Choose where to show changes and run the comparison. Set Show changes in to New document when that option is available. This keeps the source files separate and opens a comparison document with markup. Then select OK. Word analyzes the two files and displays the result. Large or heavily formatted documents may take a little time to process.
Review the redline in the comparison document. Use the Review tab’s change-navigation controls, such as Previous and Next, to move through changes. Insertions and deletions may appear as colored text, underlining, strikethrough, or balloons in the margin, depending on the display settings. Read the surrounding text before deciding whether a change is meaningful; a moved paragraph or a formatting adjustment can affect more than the marked words.
Adjust the markup display if needed. On the Review tab, use Display for Review and select a view such as All Markup to see edits, or Simple Markup for a less crowded view. Use Show Markup to control whether comments, formatting, insertions, or deletions appear. Hiding a category changes what you see, not what is in the comparison. Switch back to All Markup before concluding that no changes remain.
Save and share the comparison document. Use File > Save As or Save a Copy, depending on your version, and give the redline a distinct name, such as Report_comparison.docx. Keep the original and revised files too; the comparison is a separate working copy, not a replacement for either source. If recipients need a fixed-layout view, export or save a PDF copy after checking the redline, while retaining the Word version for further review.

To turn the redline into an agreed version: review each change and use Accept or Reject on the Review tab. You can accept or reject an individual change, or use the drop-down beside the command for options that apply to all changes. Avoid accepting everything automatically unless the reviewer has explicitly approved every edit. Save the result under a new name so the marked comparison remains available.

For edits made from now on: use Review > Track Changes before editing the document. Track Changes records new edits as you work; Compare is for finding differences between two existing versions. You can use Compare to create a redline first, then continue reviewing or editing that comparison with Track Changes enabled if appropriate.

Common Mistakes

Reversing the source files. Choosing the later file as the original can make insertions and deletions read backward. Verify the document names and dates in the dialog before selecting OK.
Comparing the wrong copies. Documents named Final, Final2, or Latest may not be the versions you expect. Open both files and confirm a distinctive paragraph or revision before comparing.
Editing a source instead of the comparison. Word opens a new result, and it is easy to save or share the wrong tab. Check the title bar and save the result with a separate comparison name.
Assuming hidden markup was removed. Simple Markup or a filtered Show Markup view can conceal changes without deleting them. Use All Markup and enable the relevant categories before reviewing or printing.
Treating formatting noise as content changes. Different fonts, spacing, headers, or page settings can generate many marks. If those are not part of the review, adjust the comparison options and run the comparison again.
Accepting all changes before reading them. Accepting a change removes its pending status. Review the text in context first, and preserve an unaltered copy of the redline.

Tips

Use a consistent naming convention. Include a date, version number, or status in each file name, such as Policy_v1_2026-10-12.docx and Policy_v2_2026-10-20.docx. This helps you identify the intended baseline months later.
Compare like with like. Keep both documents in the same file format when possible. Converting one from PDF or another word processor can change line breaks, tables, or styles, creating differences that are not actual editorial edits.
Decide whether formatting matters. Keep formatting comparison enabled for a layout or template review. Turn it off when your main question is whether the wording changed. The best setting depends on the purpose of the redline.
Check headers, footers, tables, and footnotes. Do not review only the main body. Scroll through the whole document and inspect areas where changes can be easy to miss, including text boxes, captions, numbered lists, and table cells.
Use a useful change label. A label such as Contract review or Copy edit is easier to recognize than a generic label. A label describes the comparison; it does not prove the identity or authorization of the person who made a change.
Keep the redline editable. Save as a Word document if someone must accept or reject changes. A PDF is convenient for reading and sharing, but it is not the best format for continuing a Word review workflow.

Troubleshooting

The Compare command is missing or unavailable: Make sure you are using the desktop Word app and that a document is open. Select the Review tab and look for Compare in the ribbon or its overflow menu. If you are using Word for the web, open the document in the desktop app; the browser interface may not expose the same comparison controls.
Word says it cannot open a selected file: Open the file directly first. Confirm that it is not damaged, blocked, password-protected, or still downloading from cloud storage. If it is a PDF or another unsupported format, open or convert it to Word, save a .docx copy, and compare that copy.
The redline looks empty: Check that you selected the correct two files, then choose All Markup and enable insertions and deletions under Show Markup. If the documents truly contain identical text and formatting in the selected categories, there may be no changes to display.
There are too many changes: Reopen Compare and review the More options. Turn off formatting comparison if layout differences are cluttering the result. Also check whether a conversion or different template changed styles throughout the document; those changes may be legitimate formatting differences rather than text edits.
Changes appear backward or have confusing labels: Run Compare again with the earlier file in Original document and the newer file in Revised document. Choose a clear label. The wrong direction does not alter the source files, so you can create a corrected comparison without repairing either original.
The comparison layout differs from the examples: Word updates its ribbon and dialog across versions and platforms. Look for Compare or Compare Documents on the Review tab, and consult Word’s in-app Help if the command has moved. On Mac, menu placement and some options can differ from Windows, but the same basic task is to choose the original and revised documents and create a comparison.

Frequently Asked Questions

Does comparing documents change either original file?
Normally, no. Word creates a separate comparison document when you choose New document. Save that result separately, and avoid choosing an option that displays changes in one of the source documents if you want to keep both originals untouched.

Is Compare the same as Track Changes?
No. Compare finds differences between two files that already exist and presents them as markup. Track Changes records edits made after the feature is turned on. Compare is useful for reconstructing a redline when edits were made without tracking.

Can I compare documents in Word for the web?
Availability can vary by account and version, and the web app may not provide the same Compare workflow as desktop Word. If you do not see the command, choose to open the files in the desktop Word app and use Review > Compare there.

Can Word compare a Word document with a PDF?
Compare works best with editable Word documents. Convert the PDF to a Word file first, then inspect the converted text and layout before comparing. PDF conversion can alter formatting or recognition of text, which may create misleading differences.

Can I accept only some of the changes?
Yes. Select a change and use Review > Accept or Review > Reject, then move to the next one. You can keep unresolved edits in the file while applying only the decisions that have been approved.

How do I make a clean copy after reviewing the redline?
Accept or reject the approved changes, then save the result with a new name. If markup still appears, use Review > Display for Review to check the view and confirm that no changes remain before sharing a clean version.

Try it: the Date Difference Calculator: days, months, years and weekdays between two dates, with the DATEDIF formulas.

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Sources: Function behaviour and menu paths: Microsoft Support documentation for Excel. Method & sources

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