Compare Two Word Documents and Save the Marked Result Separately

By ON Lab · Sources checked November 6, 2026

In desktop Word for Windows, use Review → Compare, identify the original and revised files, and show the changes in a New document. Save that comparison result with its own filename. When reopening it, display the tracked changes; saving one of the source files is not the same as saving the comparison.

Choose comparison rather than a side-by-side view

A Word reader ran a comparison, saved a document, and later could not see where the differences were identified. The durable output of Word's comparison is a document containing revision marks. Its on-screen arrangement is a separate matter from which document was saved and how markup is displayed.

Use Compare when you have two versions and want a marked record of their differences. Use View → View Side by Side when you simply want to read two open documents together; Synchronous Scrolling can move both views. A side-by-side view does not itself create a third document marking the differences.

Microsoft distinguishes comparing two versions from combining revisions from multiple reviewers. If the job is merging several reviewers' tracked edits, use the appropriate Combine workflow rather than treating every file as an original-versus-revised comparison.

1. Identify and preserve both inputs

Keep the original files. Give the versions clear names and check their folders before opening the Compare dialog. For example, project-notes-before.docx and project-notes-after.docx communicate the direction better than two unrelated files both called Document.docx.

The Original document should represent the baseline. The Revised document should be the version whose changes you want to see against it. Reversing them changes how additions and deletions are interpreted, even though you are looking at the same pair of files.

2. Set up a new comparison result

Open the two intended documents in Word for Windows desktop.
On Review, use the Compare group and choose Compare two versions of a document, also described by Microsoft as the legal blackline option.
Under Original document, browse to and verify the baseline file.
Under Revised document, browse to and verify the other file.
Choose what to compare, such as text, comments and formatting.
Choose whether to show changes at word or character level.
Read Show changes in and select New document.
Only then confirm the comparison.

Microsoft says the default output is a new document. The dialog can instead place results in the original or revised document, which modifies that selected file. Do not assume the default is still selected if you previously changed it.

The settings determine what the report includes. A comparison that excludes formatting is not evidence that formatting is identical. Character-level differences can be useful for a small spelling edit, while word-level output can be easier to review for ordinary text. Select the detail appropriate to the task and record it if someone else must reproduce the comparison.

3. Read any existing tracked-change prompt

If either input already contains tracked changes, Word can display a message before comparing. Microsoft's description explains that accepting that prompt accepts existing changes for the comparison process; the new result shows changes from the revised version as tracked changes.

Do not click through that prompt without considering whether you need to preserve or separately review the earlier revision history. The source-preserving new-document route and your original copies matter here. A generated comparison is not a substitute for understanding unresolved review changes in its inputs.

4. Save the third document, not an input

When the result appears, identify the comparison document's window. Use Save As and a distinct result name such as project-notes-comparison.docx. Read the full destination folder and filename before saving. Avoid overwriting either the original or revised input.

Do not accept or reject all changes if the purpose is to retain a marked difference report. That would resolve the revision marks rather than preserve them for review. Likewise, exporting a clean-looking view is not proof that you retained an editable comparison result.

5. Reopen the actual saved result

Close the comparison result after saving.
Reopen that exact result file from its saved location.
Use the Review controls to display All Markup, including the relevant change types and reviewers.
Inspect a known difference and check that the addition, deletion or formatting change is represented in the intended direction.
Use the Reviewing Pane if a summary helps you inspect the remaining changes.

The official tracked-change guidance explains that No Markup hides revision marks rather than removing them. If the result looks clean, inspect the display settings and file identity before concluding that the comparison disappeared.

If the result is empty or does not match expectations

Verify that the two inputs are actually different versions, that their order is correct, and that the comparison includes the type of change you expected. Check the saved result rather than whichever source document happens to be open.

If the output still seems wrong, create a separate small test pair with one obvious non-sensitive text edit and compare that pair. Keep any product error and the selected settings when requesting support. This guide does not guarantee perfect comparison of every complex document or diagnose a particular comparison-engine defect.

Completion means a separately saved, reopened comparison document with the expected visible revision marks. It is not an approval of the revised content, a merge of all reviewers' work, or proof that the two inputs match in every property. These steps follow Microsoft's Windows desktop documentation; no private document or reader installation was accessed to prepare them.