How to Compare Two Contract Versions in Word (Redline)

Compare vs Combine: pick the right tool first

Word ships two document-merging features under Review → Compare, and choosing the wrong one is the most common reason a redline comes out garbled.

Compare (Word labels it "legal blackline") answers the question: what is different between these two files? It takes an original and a revised version — neither needs tracked changes — diffs them, and produces a brand-new third document in which every difference appears as a tracked insertion or deletion. This is the tool for the classic negotiation scenario: opposing counsel returns a "clean" draft and claims the changes were minor, and you need to see exactly what moved.

Combine answers a different question: how do I merge markup from multiple reviewers into one document? It takes two copies of the same draft, each carrying tracked changes from a different person, and folds them together while preserving each reviewer's attribution. If your partner and your client each redlined separate copies of the same MSA, Combine puts both sets of edits into a single working document. It only handles two documents at a time, so for three or more reviewers you combine pairwise: merge copies one and two, then combine that result with copy three, and so on.

Rule of thumb: no tracked changes in the inputs and you want to discover the differences — Compare. Tracked changes already in the inputs and you want to consolidate them — Combine.

Step-by-step: running a legal blackline with Compare

1. Open Word (any document, even a blank one — Compare doesn't operate on the active file) and go to Review → Compare → Compare…
2. Set the Original document to the earlier version and the Revised document to the later version. Use the folder icons to browse if the files aren't in the recent list. Getting the order backwards inverts every insertion and deletion, so double-check it.
3. Set "Label changes with" to the name you want shown on each revision — typically the counterparty's name or "v2 changes."
4. Click "More >>" to expand the comparison settings. For contract work the useful defaults are: keep Insertions and deletions, Moves, and Tables checked; consider unchecking Formatting, Case changes, and White space to cut cosmetic noise; set Show changes at to Word level (character level is noisier and harder to read); and set Show changes in to New document so neither source file is modified.
5. Click OK. If either source contains unresolved tracked changes, Word warns that it will treat them as accepted for the purpose of the comparison — this is why hygiene (next section) matters.
6. Review the result. Word opens a comparison document with every difference as a tracked change. Use Compare → Show Source Documents to display the original and revised versions in side panels, and the Reviewing Pane for a running list of every revision with a count by type.
7. Save the comparison as its own file (e.g., MSA - Acme - compare v3 vs v4.docx). Don't accept or reject changes in it if it exists purely as a record of what the other side did — accepting changes collapses the evidence.

Merging multiple reviewers' markups with Combine

Go to Review → Compare → Combine…, set one marked-up copy as Original and the other as Revised, and confirm. Two things to know before you click OK:

• Formatting can only come from one document. If the two copies contain conflicting formatting changes, Word prompts you to keep formatting from one or the other — it cannot merge both. Pick the copy whose styles you trust, and re-apply anything lost from the other manually.
• Attribution survives. Each reviewer's tracked changes keep their author name and color in the combined document, so you can filter by reviewer with Review → Show Markup → Specific People and accept or reject one person's edits at a time.

For more than two reviewers, work in rounds: combine A with B, save the result, combine the result with C. Keep the intermediate files until the consolidated draft is agreed — if a merge goes wrong, you'll want to rewind one step rather than start over.

Track-changes hygiene before you compare

Most "Word's compare is broken" complaints trace back to dirty inputs. A few minutes of preparation makes the redline dramatically cleaner:

• Resolve pending tracked changes in both files first: Compare silently treats unaccepted edits as accepted. If the "original" still carries last round's markup, your blackline will mix old and new changes with no way to tell them apart. Accept or reject everything, then compare.
• Compare .docx against .docx: never compare against a PDF that Word has converted on the fly. Conversion reflows line breaks, hyphenation, and spacing, and every reflow shows up as a change. If the counterparty only sends PDFs, ask for the Word file — in most negotiations that's a routine request.
• Decide what to do with comments: the comparison settings include a Comments checkbox. Include them if the margin commentary matters to the negotiation record; exclude them if you only care about text changes.
• Use disciplined file names: date-stamped, party-stamped names (SaaS-MSA-Acme-2026-06-11-counterparty-turn.docx) beat Contract_FINAL_v2(3).docx every time. You cannot run a reliable compare if you're not certain which file is actually the later version.
• Inspect metadata before sending a redline out: comparison documents carry author names and revision history. Run File → Info → Check for Issues → Inspect Document before anything leaves the building, and confirm your firm's metadata policy allows sending a native .docx redline at all.
• Read in All Markup view: Review → Tracking → All Markup shows every change inline. Simple Markup looks tidier but hides deletions behind a change bar — dangerous when the deletion is the word "not."

Where Word's Compare struggles on long contracts

For a five-page NDA, Compare is usually all you need. On a 60-page credit agreement or MSA with schedules, four problems show up reliably:

• Renumbering cascades. Insert one new section 4.2 and every automatically numbered clause, cross-reference, and TOC entry after it renumbers. The redline then flags dozens of "changes" that are pure numbering fallout, burying the three edits that actually matter.
• Tables come out as wreckage. Merged or split cells, added columns, and re-sorted rows in pricing schedules often render as wholesale delete-and-reinsert blocks rather than targeted edits, forcing a manual cell-by-cell read.
• Moved text reads as delete + insert. The Moves setting catches clean relocations, but a clause that was moved and lightly edited typically appears as a full deletion in one place and a full insertion in another — and the light edit hides inside the reinserted block, which is exactly where a quiet "sole remedy" insertion likes to live.
• A diff is not a review. This is the structural limitation: Compare shows what changed, never what it means. A one-word swap of "shall" for "may" in an indemnity, a deleted "not," or a liability cap that quietly moved from 12 months of fees to 3 gets the same visual weight as a fixed typo. On a long redline at 6 p.m., that's how bad changes get initialed.

Practical mitigations: turn off formatting comparison, compare at word level, and review section by section rather than scrolling the whole markup. But the fourth problem — no substantive analysis — isn't something a settings change fixes.

The purpose-built path: clause-level comparison with LexDraft

LexDraft's free contract comparison tool picks up where the mechanical diff stops. Instead of diffing whole files, you paste the original clause and the revised clause side by side, tell it the governing jurisdiction, which side of the deal you're on, and optionally the contract type — and it returns an analysis of what changed, the key changes and their impact, and which revisions are favorable or unfavorable to your side. That's the question Word's blackline can't answer.

The two tools work best as a sequence:

1. Run Word's Compare to locate which sections the counterparty touched.
2. Skim the redline and triage: numbering noise and typo fixes get accepted; substantive sections — indemnification, limitation of liability, termination, IP, payment — get flagged.
3. Paste each flagged clause pair into the comparison tool for the substantive read: what shifted, in whose favor, and how much it matters from your side of the table.

And when the analysis tells you a clause needs to be rewritten rather than accepted, the LexDraft add-in does the drafting without leaving Word — clause suggestions built on attorney-drafted standards across US federal and state jurisdictions, starting from the templates library. See the features overview for how drafting, review, and the clause library fit together, and the free tools hub for the rest of the browser-based utilities.

Frequently asked questions