Why compare documents instead of reading both?
Reading two versions side by side feels thorough, but it fails on exactly the changes that matter. A deleted 'not', a changed date, a number moved one decimal place, a clause quietly dropped from page 14: the eye skips over all of these. Lawyers learned this a long time ago, which is why a marked-up comparison of two contract drafts is called a redline or a legal blackline.
A comparison tool reads both files word by word and marks what changed. You review the marks instead of the whole text, so a 40-page document with three edits takes two minutes instead of an hour.
How to compare two Word documents with Review > Compare
Word for Windows and Word for Mac both have this built in. You need both files saved somewhere you can browse to. They do not need to be open.
If you do not have Word on this computer, jump to the online method below: Compare Word does the same job on two .docx files in the browser.
- Open Word with any document, or a blank one. Go to the Review tab and click Compare, then Compare again in the small menu.
- Under Original document, pick the earlier version. Under Revised document, pick the later one. The order matters: Word reports changes as edits made to the original.
- Click More to choose what to flag. Leave Insertions and deletions, Moves, Tables and Formatting checked. Under Show changes in, keep New document so neither file is touched.
- Click OK. Word opens a new window with the compared document in the middle, the original and revised files in panes on the right, and a Revisions pane on the left listing every change.
- Save the compared document under a new name if you want to keep it or send it. The two source files are unchanged.
Compare or Combine: which one do you need?
Compare works on two clean documents. It ignores who edited what and simply reports the differences, attributing them all to one author. Use it when a colleague or the other side sent back a revised file with Track Changes switched off, or when you want to know what changed between two saved versions.
Combine, right next to it in the same menu, is for documents that already contain tracked changes from several reviewers. It merges the revisions of two copies into one document and keeps the author names and colors, so you can see that Maria deleted the second paragraph and Dan reworded the heading. You can combine more than two copies by running it again on the result.
Rule of thumb: no tracked changes in the files means Compare. Tracked changes from several people means Combine.
What Word's Compare shows and what it misses
Compare catches text that was inserted, deleted or moved, changes to tables, and formatting changes such as bold, font size or paragraph spacing when the Formatting box is checked. It also compares headers, footers, footnotes, text boxes and fields when those options are on.
It has limits worth knowing. If a sentence was rewritten heavily, Word shows the whole old sentence deleted and the whole new one inserted rather than the individual words, which is correct but harder to read. Changes inside pictures, charts, embedded spreadsheets and SmartArt are not described; you see at most that an object was replaced. A scanned PDF or a photo of a page cannot be compared at all until the text is recognized.
Compare also only works with Word formats. If one side is a PDF, a Google Doc or a Pages file, convert it to .docx first, which is covered below.
Track Changes is the better habit
Comparing after the fact is a repair job. The cleaner approach is to turn on Track Changes before anyone edits, so each change is recorded as it happens with the author's name and the time. Go to Review, Track Changes, and leave it on. On a shared OneDrive or SharePoint file you can also lock tracking with a password so nobody switches it off.
When the document comes back, use Review, Next and Accept or Reject to walk through the edits, exactly as you would with a compared document. The difference is that you get the author per change and you do not depend on having the original to hand. If a file comes back with no marks and you suspect edits, run Compare against your copy.
How to compare two Word documents online
If Word is not installed, or you are on a phone or a Chromebook, an online comparison does the same job. DocGopher's Compare Word takes two .docx files and shows every change between them, with deleted text struck through and insertions underlined. It is free, needs no sign-up and adds no watermark. Files are processed in memory and deleted after 30 minutes, and each file can be up to 300 MB.
Old .doc files from Word 97-2003 should be upgraded to .docx first with DOC to DOCX, and a document from LibreOffice can go through ODT to DOCX.
- Open the Compare Word page in any browser.
- Upload the original version first, then the revised version. The order sets which text counts as deleted and which as inserted.
- Run the comparison and read the result on screen. Deleted text is struck through, inserted text is underlined.
How to compare documents in Google Docs
Google Docs has two features that cover most comparison needs. The first is Tools, Compare documents. Open the older version, choose Tools, Compare documents, pick the newer version from Drive, and set a name under Attribute differences to. Docs creates a new file with the differences shown as suggested edits, which you can accept or reject one by one.
The second is version history. Go to File, Version history, See version history. The panel on the right lists every saved state with the date and the person who edited. Click a version and the changes made since the previous one are highlighted in that editor's color. You can name important versions and restore any of them.
To compare a Word file in Docs, upload it to Drive and open it with Google Docs. Docs converts it on the fly, and the comparison works the same way. Fonts and some layout details may shift in the conversion, but the text comparison stays accurate.
How to compare a PDF to a Word document
Word cannot compare a PDF directly, so convert the PDF to .docx first. Word for Windows will open a PDF and convert it (File, Open, pick the PDF, then OK on the warning), which works well for simple text documents. For PDFs with tables or columns, PDF to Word rebuilds the layout and tables in the .docx, which gives Compare less noise to report.
Two things to expect. Line breaks in a PDF often become paragraph marks in the conversion, so Compare may flag paragraph changes that are not real edits; uncheck Formatting in the Compare options to quiet those. And if the PDF is a scan, there is no text to convert until you run OCR on it; the recognized text will contain small errors, so treat flagged single-character changes with suspicion.
Once both sides are .docx files, run Compare as described above, or upload both to Compare Word.
How to read the comparison result
In Word, the compared document uses the standard markup: deleted text in red with a strikethrough, inserted text underlined, moved text in green with a double line, and formatting changes noted in a balloon or in the Revisions pane. A vertical bar in the left margin marks every line that contains a change.
Use Review, Next to jump from one change to the following one, and Accept or Reject to decide. Accept All turns the compared document into a clean copy of the revised version. If the markup is too busy, set Display for Review to Simple Markup to see only the margin bars, or to No Markup to read the final text.
The Revisions pane header shows the total count of insertions, deletions, moves and formatting changes. If it reports hundreds of formatting changes and few text changes, the revised file was probably saved from a different program; rerun Compare with Formatting unchecked.
Frequently asked questions
How do I compare two Word documents for differences?
In Word, go to Review, Compare, Compare, choose the original and the revised document, and click OK. Word creates a new document with deletions struck through and insertions underlined. Without Word, upload both .docx files to a free online tool such as DocGopher's Compare Word.
What is the difference between Compare and Combine in Word?
Compare reports the differences between two documents without tracked changes and attributes them to a single author. Combine merges the tracked changes already present in two copies of a document and keeps each reviewer's name and color.
Can I compare two Word documents in Google Docs?
Yes. Open one document, go to Tools, Compare documents, select the other file from Drive, and Docs creates a new document with the differences shown as suggested edits. Version history under File shows changes between saved versions of the same file.
Can Word compare a PDF to a Word document?
Not directly. Convert the PDF to .docx first, either by opening it in Word for Windows or with a PDF to Word converter, then use Review, Compare on the two Word files. A scanned PDF needs OCR before it has any text to compare.
Does Word's Compare change my original files?
No. With Show changes in set to New document, which is the default, Word writes the result to a third document and leaves both source files untouched. Save the result under a new name if you want to keep it.
Why does Compare show hundreds of formatting changes?
The revised file was usually saved from a different program or Word version, which rewrites fonts, spacing or styles. Click More in the Compare dialog and uncheck Formatting to see only the text changes.