SOYATOOLS / GUIDES
How to compare two Word documents and see what changed
A contract, report or proposal comes back edited, but tracked changes were off, or the changes were accepted before the file was sent. Reading both versions side by side is slow and easy to get wrong. Comparing the two files shows every added, deleted and reworded passage. Word has a Compare feature built in; a separate comparison app is another option when you want both versions side by side and a change report.
Why reading both versions is not enough
When edits arrive without tracked changes, nothing in the file tells you what is different. A changed amount, a moved clause or a deleted “not” can look almost identical on a quick read. Even when a file has tracked changes, you only see what was recorded; edits made with tracking off, or changes accepted before the file reached you, do not show up. A comparison works from the two files themselves, so it does not depend on how they were edited.
Free option: Word’s own Compare
If Word is installed on your PC, start here; it costs nothing extra. Microsoft describes these steps for Word for Microsoft 365, Word 2024 and Word 2021 (Microsoft Support: compare document differences using the legal blackline option):
- Open the two documents.
- On the Review tab, in the Compare group, select Compare, then Compare two versions of a document (legal blackline).
- Under Original document, choose the earlier file; under Revised document, choose the edited one.
- Choose what Word should compare, such as comments, formatting and text changes, and whether to show changes at character level or word level. Select OK.
- If either document contains tracked changes, Word shows a message; select Yes to accept those changes and compare.
By default Word creates a new, third document in which the differences appear as tracked changes, and the two source documents are not changed. If you choose to show the changes in the original or revised document instead, that document is modified, so keep a copy. For merging edits from several reviewers, Microsoft points to combining revisions rather than comparing.
When a separate comparison app helps
- Word is not installed on the PC you are using.
- You prefer to see the original and the revised file side by side, with the changes highlighted and a list you can filter by type, instead of reading a document of tracked changes.
- You need a PDF or XLSX report of the changes to send to someone (Pro).
- The same comparison is needed for text PDFs or spreadsheets, not only Word files.
Compare two .docx files with Compare Documents
- Install Compare Documents from Microsoft Store.
- Open the original and the revised file. Both must be of the same kind, for example two .docx files.
- Read the summary and browse the highlighted changes side by side. Filter the change list by type and move to the previous or next change.
- With Pro, adjust the comparison options, review all changes and save a PDF or XLSX report.
For Word documents the app compares:
- Added, deleted and reworded text, word by word.
- Paragraphs that moved, even when they were edited too.
- Changes to bold, italic, underline, font, size and color.
- Tables, footnotes, endnotes, headers, footers and text boxes.
- Tracked changes are compared as accepted.
- Old .doc files are converted locally before comparison. This is beta.
Free and Pro
| Plan | Price | Included |
|---|---|---|
| Free | Free | Run comparisons within the free file-size limits, see the summary and highlight the first 10 changes. |
| Pro yearly | $49.99/year | Every change, PDF and XLSX reports, comparison options and large files. |
| Pro monthly | $7.99/month | The same Pro features. |
Pro has a 1-week free trial. Microsoft Store handles subscriptions, prices and trial eligibility. Pro options include ignoring case, spaces, number formatting or formatting changes. Pro is required for documents over about 120 pages (and for PDFs over 100 pages or spreadsheets over 10,000 rows).
Measured results and limits
The tests used pairs of an original and an edited copy with a known set of changes, made for the tests or taken from public files. For Word documents, 38 of 39 pairs were exactly right; the remaining pair reported one extra moved paragraph. These are results for those pairs, not a guarantee for every file.
- .doc conversion is beta.
- Scanned PDFs that contain only images are not supported; the app tells you when it cannot find text.
- Check important changes in the original files before you rely on them.
Are my documents uploaded?
No. Reading, comparison and report generation run on your PC, and no documents are uploaded. Microsoft Store handles licensing and subscriptions. See the product page for the Privacy Policy.
FAQ
Does Word have a free compare feature?
Yes. In Word for Microsoft 365, Word 2024 and Word 2021, Review > Compare > Compare two versions of a document (legal blackline) creates a new document showing the differences as tracked changes. See Microsoft’s instructions.
What happens to tracked changes that are already in the files?
Compare Documents compares tracked changes as accepted. Word asks you to accept them for the comparison when either document contains them.
Can I compare old .doc files?
Yes, as a beta: the app converts .doc files locally before comparing them.
How long can a document be on the free plan?
The free plan works within the free file-size limits and shows the summary and the first 10 changes. Documents over about 120 pages need Pro.
Can it compare PDFs or Excel files too?
Yes. It compares text PDFs (original pages side by side, with boxes around changes) and .xlsx, .xls and .csv files. Image-only scanned PDFs are not supported, and .xls files are compared by values only.