What Is Contract Redlining? How Lawyers Mark Up Agreements

The average commercial contract goes through 3.4 rounds of negotiation before execution. Each round involves at least two lawyers marking up the same document, tracking who changed what, and trying not to lose revisions in an email chain that has grown to 47 messages. According to the World Commerce & Contracting 2025 Benchmark Report, organizations experience an average of 8.6% value erosion in their contracting processes — and much of that waste happens during the redlining phase.

Redlining is the process of marking proposed changes to a contract so that all parties can see exactly what has been added, deleted, or modified. It’s the mechanism by which lawyers negotiate. And despite being the single most time-consuming activity in contract work, most lawyers learn it by trial and error rather than formal training.

This guide covers what contract redlining is, where the term comes from, how the process works in practice, the tools lawyers use, and the etiquette and best practices that separate clean negotiations from chaotic ones. If you want to see how AI handles the redlining process, try Clause Labs’s free contract analyzer — it generates suggested redlines with tracked changes and plain-English explanations in under 60 seconds.

Where the Term “Redlining” Comes From

The term is literal. Before word processors existed, lawyers reviewed contracts on paper and used red pens to mark changes. Red ink stood out against the black printed text, making edits immediately visible. Additions were written in the margins. Deletions got a red line drawn through them — hence “redlining.”

According to the ABA’s article on track changes and redlining, this manual process worked for short agreements but became impractical as contracts grew longer and more complex. A 50-page MSA with changes from three parties produced a document so marked up that it was nearly unreadable.

The shift to digital happened in stages:

• 1980s-1990s: Word processors introduced basic revision tracking
• 1995-2000s: Microsoft Word’s Track Changes feature became the de facto standard for legal markup
• 2010s: Cloud-based collaboration tools (Google Docs, SharePoint) added real-time co-editing
• 2020s: AI-powered tools began generating suggested redlines automatically, analyzing contracts and proposing specific changes based on risk analysis and legal playbooks

Today, “redlining” refers to the entire process of proposing, reviewing, and negotiating contract changes — regardless of whether anyone picks up a red pen.

How Contract Redlining Works in Practice

The Basic Workflow

1. Party A drafts the initial contract (the “first draft” or “send-out draft”). This version favors Party A’s interests.

2. Party B’s lawyer reviews the draft and marks up proposed changes using Track Changes in Microsoft Word. Additions appear in colored text. Deletions appear as strikethrough text. Comments explain the reasoning behind significant changes.

3. Party B returns the redlined draft to Party A.

4. Party A reviews Party B’s redlines, accepts some changes, rejects others, and proposes counter-edits. This produces a new redlined version.

5. The cycle repeats until both parties agree on final language. The agreed version is “turned clean” (all changes accepted, Track Changes turned off) and sent for signature.

Redlining vs. Blacklining

These terms are often confused:

• Redlining is the active process of marking changes in a document. The lawyer edits the contract with Track Changes on, adding and deleting language.
• Blacklining (or “legal blacklining”) is a comparison function. Microsoft Word’s Compare Documents feature produces a blackline — a new document showing every difference between two versions. As LexCheck’s comparison of the two concepts explains, blacklining is useful when you receive a “clean” revised draft without tracked changes and need to see what the other side actually changed.

Why this matters in practice: If opposing counsel sends you a “clean” revised version without Track Changes, always run a blackline comparison against the previous version. Changes made without Track Changes — whether intentional or accidental — are a common source of contract disputes.

Tools Lawyers Use for Redlining

Microsoft Word Track Changes

Still the dominant tool for legal redlining. Word’s Track Changes feature records every insertion, deletion, and formatting change, showing who made each edit and when.

Key features for legal work:
– Simple Markup vs. All Markup display modes
– Accept/Reject individual changes or all changes at once
– Compare Documents (for generating blacklines)
– Combine Documents (for merging edits from multiple reviewers)
– Restrict Editing to prevent unauthorized changes to certain sections
– Mark as Final to indicate the document is ready for signature

According to the ABA’s 2024 Legal Technology Survey, Microsoft Word remains the word processor used by over 95% of law firms for contract drafting and negotiation.

Common pitfalls:
– Metadata leaks: Word files can contain hidden Track Changes history, comments, and author information. Always run the Document Inspector before sending externally.
– Version confusion: Emailing redlined documents back and forth creates version control problems. Name files systematically (e.g., “MSA_ClientCo_Redline_v3_2026-02-15.docx”).
– Hidden changes: If Track Changes was turned off during editing, those changes won’t appear in the markup. Always verify with a blackline.

Google Docs Suggesting Mode

Google Docs’ “Suggesting” mode functions similarly to Word’s Track Changes. Suggested edits appear as colored insertions and deletions that can be accepted or rejected individually.

Advantages: Real-time collaboration, automatic version history, no email attachments.
Limitations: Less common in legal practice, limited formatting control, fewer firms accept Google Docs for contract negotiation. Most opposing counsel expect a Word document.

Contract Lifecycle Management (CLM) Platforms

Enterprise tools like Ironclad, DocuSign CLM, and Icertis provide built-in redlining within broader contract management workflows. These platforms offer version control, approval routing, and audit trails — but they’re designed for in-house legal teams managing high volumes, not for solo practitioners negotiating individual deals.

AI-Powered Redlining Tools

The newest category. AI redlining tools analyze a contract, identify provisions that deviate from a standard playbook, and suggest specific edits automatically. The lawyer then reviews, accepts, or modifies the AI’s suggestions.

The Thomson Reuters 2025 report on AI in professional services found that 26% of legal organizations were actively using generative AI in 2025, with document review and contract analysis among the top applications. By 2026, that number has continued to rise.

Clause Labs generates AI redlines as part of its contract review pipeline — uploading a contract produces not just a risk analysis but specific suggested edits displayed as tracked changes. Lawyers can accept or reject each suggestion individually, then export the result as a Word document with proper tracked changes formatting. Upload any contract to see AI-generated redlines — the Solo plan ($49/month, 25 reviews) includes DOCX export with proper tracked changes, ready to send to opposing counsel.

For a deeper look at how AI redlining compares across different tools, see our comparison of the best AI contract review tools.

Redlining Etiquette: The Unwritten Rules

Every experienced lawyer knows these rules, but they’re rarely taught formally. Violating them signals inexperience and can damage the negotiating relationship.

1. Always Use Track Changes

Never send a revised contract without tracked changes unless you explicitly tell the other side you’re sending a clean version. Sending a “clean” document with hidden changes is considered a breach of professional courtesy — and in some jurisdictions, it could raise ethical concerns under ABA Model Rule 8.4 (misconduct) if done intentionally to deceive.

2. Don’t Redline Every Word

Changing “shall” to “will” throughout a 40-page agreement sends a message: you’re more interested in imposing your style than negotiating substance. Focus your redlines on provisions that change the parties’ rights, obligations, or risk allocation. Leave stylistic preferences aside unless they create legal ambiguity.

3. Explain Significant Changes in Comments

For any redline that materially changes a party’s obligations, add a comment explaining your reasoning. “Deleted because one-sided” is more productive than a deletion with no explanation. Comments reduce the number of negotiation rounds by helping opposing counsel understand your position without a phone call.

4. Don’t Reject and Re-Insert

Rejecting the other side’s language and then re-inserting identical or nearly identical language (often in a different color) is confusing and counterproductive. If you’re rejecting a proposed change, leave it rejected. If you want to modify it, accept their change first, then make your counter-edit with a new tracked change.

5. Turn Your Redline Before Sending

After marking up the document, review your own changes. Are they consistent? Do your edits in Section 3 conflict with language you left unchanged in Section 8? Does the defined term you changed on page 2 still work on page 15? A sloppy redline undermines your credibility.

6. Number Your Drafts

Use a clear naming convention. Something like:
– MSA_CompanyA_CompanyB_Draft1.docx (initial send)
– MSA_CompanyA_CompanyB_Draft2_CompanyB_Redline.docx (counterparty’s markup)
– MSA_CompanyA_CompanyB_Draft3_CompanyA_Response.docx (your response)

This prevents the “which version are we on?” problem that derails negotiations.

Common Redlining Mistakes

1. Editing with Track Changes Off

It happens more often than anyone admits. The lawyer edits the document, forgets to turn on Track Changes, and sends a “clean” version that contains hidden modifications. The other side runs a blackline, discovers the changes, and trust evaporates.

Prevention: Set Word to always track changes when opening certain document types, or use the “Lock Tracking” feature that requires a password to turn off Track Changes.

2. Failing to Run a Blackline on Incoming “Clean” Drafts

If opposing counsel sends a clean version, you must compare it against the last version you sent. Our guide to reviewing contracts for red flags covers this as a critical step in every review process.

3. Metadata Exposure

Track Changes history can reveal internal strategy — deleted comments from your partner, draft language you considered and rejected, author names that show who at your firm worked on the document. Always strip metadata before sending a redlined document externally.

How to strip metadata in Word:
File > Info > Check for Issues > Inspect Document > Document Inspector > Remove All

4. Losing Track of Versions

With multiple rounds of redlines flying between parties, it’s easy to respond to an outdated version. This creates conflicting edits that take hours to untangle.

Solution: Maintain a version log. Note the date each version was sent and received, by whom, and the key changes in that round.

5. Over-Redlining as a Negotiation Tactic

Some lawyers mark up every provision in a contract as a power move. This backfires. It tells the other side you’re either unreasonable or didn’t read the document carefully enough to identify what actually matters. Focused, substantive redlines carry more weight.

Redlining in the Age of AI

AI is changing how lawyers approach redlining in three specific ways:

1. Automated first-pass redlining. AI tools analyze a contract against a defined playbook (set of rules about acceptable and unacceptable provisions) and generate initial markup. The lawyer reviews the AI’s suggestions rather than reading every clause from scratch. This is what Clause Labs does — the AI generates suggested edits with tracked changes, and you accept or reject each one.

2. Consistency checking. AI can verify that your redlines are internally consistent — that a defined term changed in Section 1 is updated throughout the document, that a liability cap change in Section 7 doesn’t conflict with the indemnification carve-out in Section 9.

3. Risk-based prioritization. Instead of reading a 50-page contract linearly, AI identifies the highest-risk provisions first. Gartner predicts that AI and contract analytics are urgent priorities for general counsel, with organizations using AI in contract management cutting review time by up to 50%.

What AI doesn’t replace: the strategic decisions about what to push for, what to concede, and how to frame your position. Redlining is negotiation in written form. AI handles the pattern matching and error checking. The lawyer handles the judgment.

For a detailed comparison of AI contract review tools that include redlining capabilities, see our comprehensive guide to AI contract review tools.

Frequently Asked Questions

Is redlining the same as editing a contract?

Not exactly. Redlining specifically refers to making visible, trackable changes during contract negotiation — so all parties can see what was changed and by whom. Editing is a broader term that includes internal revisions not shared with the other side.

How many rounds of redlining is normal?

For a standard commercial contract (NDA, simple services agreement), 1-2 rounds. For complex agreements (MSAs, M&A documents, technology licenses), 3-5 rounds is typical. Anything beyond 6-7 rounds usually signals a fundamental disagreement on deal terms that should be resolved in a phone call, not through more markup.

Should I redline or call?

Both. Redlining documents the specific language changes. Phone calls (or video calls) resolve disagreements about business terms and priorities faster than exchanging marked-up drafts. The most efficient negotiators use calls to reach agreement on principles, then redlines to capture the agreed language.

Can AI replace manual redlining?

AI can generate a strong first draft of redlines based on your playbook preferences, but it cannot replace the lawyer’s judgment about what changes to propose in a specific deal context. The technology is a force multiplier, not a substitute. The ABA’s Formal Opinion 512 on generative AI makes clear that lawyers remain responsible for supervising AI-generated work product.

What format should I send redlined documents in?

Microsoft Word (.docx) with Track Changes is the universal standard in legal practice. Never send a redlined document as a PDF unless you’re specifically asked to — PDFs strip the ability to accept or reject individual changes. If you use Google Docs internally, export to Word before sending to opposing counsel.

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This article is for informational purposes only and does not constitute legal advice. Consult a qualified attorney for advice specific to your situation.

Want to see AI-generated redlines on your next contract? Upload any agreement to Clause Labs and get suggested edits with tracked changes in under 60 seconds. Export as a Word document with proper markup — ready to send to opposing counsel. Start free with 3 reviews per month.