Compare Documents in Word 365: A Practical Guide

To compare two files in Word 365 on Windows, open Word and choose Review > Compare > Compare, select the original and revised documents, then choose OK. Word creates a third document showing the differences, so your two source files stay unchanged. Have both files available and decide whether you want to compare text only or include formatting and other document elements.

What You’ll Need

Microsoft Word for Microsoft 365 desktop on Windows. Word for the web does not provide the full desktop Compare workflow; if you are editing in a browser, choose to open the files in the desktop app.
Two versions of a document that Word can open. They can be saved locally or in a location Word can access, such as OneDrive or SharePoint.
A way to identify which file is earlier and which is later. The comparison labels these as the original and revised documents, and choosing them in the correct order makes the results easier to read.
Enough access to open both files. If a file is password-protected, encrypted, or restricted by an organization, you may need permission or the password before Word can compare it.
A place to save the comparison result. Word normally creates a new comparison document, but you should still save it with a clear name so it is easy to distinguish from the two source files.

Step-by-Step

Identify and open the right files. Before starting, confirm which document is the earlier version and which is the updated version. You do not need to open both documents in separate windows first, but doing so can help you check their names and contents. If the files have similar names, note their locations or rename copies with clear labels such as Project-original and Project-revised. Avoid renaming the only source copies if your workplace has a file-naming or records policy.
Open the Compare command. In Word for Microsoft 365 on Windows, open a document or start Word, then select Review > Compare > Compare on the ribbon. If the ribbon is collapsed, expand it or maximize the Word window to reveal the commands. The Compare command is different from switching on Track Changes: it checks two existing versions and produces a marked comparison, rather than tracking edits as you make them going forward.
Choose the original document. In the Compare Documents dialog, use the file picker beside Original document to select the earlier file. Check the displayed document name before proceeding. If Word has several documents open, do not rely only on the first item in a list; choose the correct file explicitly. The original is the baseline Word uses to identify insertions, deletions, and other differences.
Choose the revised document. Use the file picker beside Revised document to select the later version. Verify that it is not the same file you chose as the original. Word can compare documents even when the file names differ only slightly, so check the folder and, if needed, open each version separately to confirm which changes it contains.
Set the comparison label and detail level. The dialog lets you enter a label for changes, such as a person’s name or a version label. Word uses that label in the comparison markup. The Show changes at setting lets you choose a more detailed character-level comparison or a broader word-level comparison. Character-level markup can make small spelling or punctuation edits obvious, but it may look busy. Word-level markup is often easier to scan when sentences or longer passages have changed.
Choose what Word should compare. Select More in the dialog to reveal additional comparison options. Depending on your version, options can include formatting, comments, moves, case changes, white space, tables, headers and footers, footnotes and endnotes, text boxes, and fields. Leave relevant items selected if you need a comprehensive review. If you only care about the wording, turn off categories that would add distracting markup, such as formatting. Be cautious about excluding comments or headers if those contain approvals, dates, or other material that matters to the review.
Choose where to show the changes, then run the comparison. Under Show changes in, choose New document for a separate result, or choose one of the source documents if you have a specific reason to display the markup there. A new document is the safest option for most reviews because it keeps the source files intact. Select OK to run the comparison. Word may take longer when documents are large or contain many tables, comments, or images.
Review the comparison document. Word opens the result with tracked-change-style markup and may show the two source documents alongside it. Use the Review tab’s navigation controls to move between changes, and inspect the Reviewing Pane if you want a list of revisions. Deleted text, inserted text, and formatting differences may appear differently depending on your markup view and display settings. If the markup is hard to read, change the display through Review > Tracking options, or use the Reviewing Pane to see a more organized list. The comparison is evidence of differences, not an automatic decision about which edits should be kept.
Save the result as a separate file. Choose File > Save As, select a suitable location, and give the comparison a name that indicates its purpose, for example, Contract-review-comparison. Save it in Word format if you need the review markup to remain editable. Keep the original and revised documents as well; the comparison file is a separate review artifact and is not a replacement for the source versions.
Decide how to apply the findings. If you need a final approved version, review each change and use the controls in Review > Changes to accept or reject it in the comparison document or in a copy prepared for editing. Do not accept all changes without reading them when the document has legal, policy, technical, or financial significance. If your goal is to bring edits from two separately revised copies together, use Word’s Combine command rather than assuming Compare will merge the content.

On Mac: In current desktop versions of Word for Mac, look for the comparison command on the Review tab, typically under Compare or Compare Documents. The dialog layout and exact labels can vary by release, but the task is the same: select the original and revised files, set the options, and create a comparison. If you cannot find the command, update Word or use Word for Microsoft 365 on Windows. Word for the web may require you to open the files in the desktop app.

Common Mistakes

Reversing the source files. Word can still show differences if the earlier and later versions are swapped, but insertions and deletions may be described from the wrong direction. Check the labels in the dialog before clicking OK.
Comparing the wrong copies. Two files named Draft-final and Draft-final-2 may not be the versions you expect. Confirm the file path and content, especially when copies are stored in email attachments, Downloads, OneDrive, or shared folders.
Expecting Compare to merge edits. Compare identifies differences and presents them for review. It does not automatically create a single approved document by resolving conflicting edits. Review and accept or reject changes, or use Combine when you need to consolidate independently edited copies.
Overlooking non-text content. A text-focused review can miss changes in formatting, comments, headers, footnotes, or other elements if those categories are excluded. Check the More options before running a comparison, and include the categories relevant to your task.
Saving over a source file. Selecting a source document as the place to show changes can make the result less clear and risk confusion about which file is the original. Prefer New document, then save the result under a new name.
Treating every marked difference as an error. A comparison reports that content differs; it cannot tell whether a change is intentional, correct, or approved. Read the surrounding passage and check the relevant source or reviewer before accepting it.

Tips

Use descriptive file names that include a date, version number, or author. That small step makes selecting the right original and revised files much less error-prone.
For a clean text review, consider turning off formatting comparison while leaving the text-related options on. If formatting itself is the subject of the review, keep it enabled and expect more markup.
Choose character-level detail for small edits, such as punctuation, a changed number, or a spelling correction. Choose word-level detail when sentence revisions are extensive and you want fewer small visual marks.
Use the Reviewing Pane and navigation controls to work through changes in sequence. A long document is easier to review systematically than by scrolling and searching for colored markup.
Keep an untouched copy of each source version, and save the comparison output separately. For collaborative work, store the result in an agreed shared location and communicate which file is the review copy.
If the comparison is unexpectedly noisy, check whether Word is reporting formatting, whitespace, or other categories you do not need. Run a new comparison with adjusted options rather than trying to infer the text-only result from a crowded view.

Troubleshooting

The Compare command is missing or unavailable. Make sure you are using the desktop version of Word rather than editing only in a browser. Maximize the window, expand the ribbon, and check the Review tab. On Mac, the command may be named or arranged slightly differently. If your organization manages Office, an administrator may control available features; check for updates or ask your support team.

Word will not open one of the files. Open each source on its own first. If Word asks for a password, enter it or request access from the file owner. If the file is damaged, try opening a known-good copy or ask the owner to resave it in a Word format. A file that is still downloading or syncing may also fail to load; wait for the sync to finish and try again.

The output shows too many changes or misses something important. Reopen Compare and inspect the options under More. Enable categories you need to check, or disable irrelevant categories such as formatting to reduce visual clutter. Also verify that you chose the intended versions and that neither file was already edited after you identified it.

Changes are difficult to see. Check the markup display and Reviewing Pane on the Review tab. The current view may hide some markup, or the selected display mode may make it less prominent. Switch to a view that displays all markup, and navigate change by change. If the document is very long, save the comparison before continuing so you can return to it.

The comparison takes a long time or Word stops responding. Large files with extensive formatting, comments, images, or tables can take longer to process. Wait before closing Word, then try again with copies of the files and fewer comparison categories if the delay continues. Close unrelated documents and applications to free resources. Do not remove comments, images, or other content from the only originals just to speed up the comparison.

Frequently Asked Questions

Does comparing documents change either original file?
Not when you choose New document under Show changes in. Word creates a separate comparison result. Save that result under a new name and retain both source files.

Can I compare two Word documents in Word for the web?
The full Compare workflow is a desktop Word feature. Open the files in the Microsoft 365 desktop app and use Review > Compare > Compare on Windows. The precise menu arrangement differs on Mac.

What is the difference between Compare and Combine?
Compare displays differences between two versions for inspection. Combine is intended to bring revisions from separately edited copies together into a document. Choose based on whether you need to review differences or consolidate edits.

Can Word compare files that have different names?
Yes. The names do not need to match. Select the correct earlier file as Original document and the correct later file as Revised document, then verify both selections in the dialog.

Why does the comparison show formatting changes?
Formatting comparison may be enabled in the additional options, or the documents may differ in styles, layout, or other formatting. Run another comparison with formatting excluded if you only need to inspect text. Keep it enabled when visual presentation is part of the review.

Can I accept or reject the differences after comparing?
Yes. The comparison result uses revision markup that you can review with the controls on the Review tab. Inspect each change before accepting or rejecting it, and save the reviewed result as a separate final copy when appropriate.

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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