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The best contract redlining software in 2026
Eight tools compared on price, how they produce redlines, playbooks, and whether they work inside Word
Artur Sapek, Founder of Revise10 min read
“Redlining” covers two tasks. One is comparing two versions of a contract and marking every difference, which produces the blackline you send back to the other side. The other is proposing the edits in the first place. Comparison software handles the first task, and AI tools propose edits as Word tracked changes. Contract lifecycle management (CLM) platforms include redlining as one part of a larger contract system. The right tool depends on which of these you need.
I have spent the past year building a word processor around an AI agent, including Word tracked changes and legal numbering. For our AI document review comparison, I tested Revise, Spellbook, and Word with Copilot, among others, on the same contract. I did not test the other tools here hands-on, so their descriptions come from each vendor’s own pages, which are linked in the sources at the end. Several legal tools do not publish prices.
Contract redlining software at a glance
The “AI capabilities” column is the most useful place to start. Most of the AI tools here produce redlines as Word tracked changes, but they differ in whether they check a contract against your playbook, where they run, and what they cost. Blacklining two versions does not require AI, though Litera Compare also has an AI agent that analyzes the risk in changes and suggests rewrites.
| Tool | Best for | Free plan | Paid from | AI capabilities |
|---|---|---|---|---|
| Spellbook | Legal AI review and redlines with playbooks, in Word | No (7-day trial) | Custom (Custom, priced per team) | Contract review, drafting, and redlines as tracked changes |
| Revise | AI redlines at a published price, with a Word round trip | Yes (daily AI limit) | $8/mo (Plus) | Agent proposes text and formatting edits as suggestions. Header, footer, and page-layout changes apply directly |
| LegalOn | Playbook review with a clause library | No (no public trial terms) | Custom (Custom) | Playbook review flags risks, AI Revise redlines in Word track changes |
| Claude for Word | A general AI assistant inside Word | No (Pro plan or higher) | $20/mo (Claude Pro) | Cites sections, edits selections, works comment threads, tracked changes when on |
| Litera Compare | Multi-format and bulk blacklines | No (no public trial terms) | Contact sales (Custom) | Deterministic redlines, Lito AI analyzes risk in changes and suggests rewrites |
| Draftable | Document comparison at a published price | Partial (free web compare, 5-day desktop trial) | $10.75/mo (Business) | None built in |
| Microsoft Word | A legal blackline built into desktop Word | Yes (Word for the web) | $9.99/mo (Microsoft 365 Personal) | Copilot drafts, rewrites, and summarizes, edits in place with highlight and undo |
| Ironclad | Redlining inside a full CLM | No (no public trial terms) | Custom (Custom) | Redlines a full contract against your playbook as tracked changes |
Word’s free plan is Word for the web, and Microsoft documents the legal blackline Compare only for desktop Word.
The second table sorts them by type. A playbook records your preferred positions so the AI can check a contract against them. Playbooks are the main feature that legal AI products have and general AI products do not.
| Tool | Type | Compares versions | Playbooks | Where it runs |
|---|---|---|---|---|
| Spellbook | Legal AI add-in | Not listed | Yes | Word add-in |
| Revise | Word processor with an AI agent | Versions of one document | No | Browser, imports and exports .docx |
| Claude for Word | General AI add-in | Not listed | Not listed | Word on Windows, Mac, and the web |
| Litera Compare | Comparison (blackline) | Yes, including bulk | - | Desktop, web, mobile, Microsoft 365 |
| Draftable | Comparison (blackline) | Yes | - | Windows desktop, web, Office integration on Legal plan |
| Microsoft Word Compare | Built-in comparison | Yes | - | Desktop Word for Microsoft 365, 2024, and 2021 |
| LegalOn | Legal AI review | Not listed | Yes, plus a clause library | Web, Word add-in |
| Ironclad | Contract lifecycle management | Not listed | Yes | Web, Word add-in |
To try AI redlining on one of your own contracts in Revise, import a .docx below and ask the agent to review it. It opens in your browser without an account, and you need a free account to accept changes.
How we evaluated them
We compared each tool against the manual workflow, where you edit a contract in Word with Track Changes on and then compare it against the last version you sent. I compared each tool’s documented workflow on the six criteria below, and I added hands-on observations where our contract test covered the tool.
- Redline output. Do changes arrive as Word tracked changes the other side can accept or reject?
- Comparison. Can it blackline two versions of a document?
- AI review. Can it propose edits, and check them against your playbook?
- Word files. What does the vendor document about numbering, comments, and existing tracked changes?
- Price. Is there a published price or a trial?
- Fit. Does it work inside Word, and does it tie into contract storage and approvals?
The ranking gives the most weight to AI redlining with tracked changes. It is a guide to which tool fits which job, not a measured quality score. If you only need to compare versions, the comparison tools at ranks five to seven may be all you need.
The 8 best contract redlining tools
1. Spellbook: Best for legal AI review with playbooks
- Free plan: No, 7-day trial
- Paid from: Custom
- Built-in AI: Spellbook
Spellbook is sold as a Word add-in for lawyers, with review, drafting, a question-answering mode, playbooks, and benchmarks against market terms. Its suggestions are redlines as tracked changes.
In our single-contract test, Spellbook gave a useful review. It first listed its suggested changes in a table, then opened the document in its browser editor and made tracked changes that survived export to Word. The changes carried the tester’s name rather than Spellbook’s, and there was no way to reply to them. Pricing is custom by team size, with a 7-day trial.
Pick it if you review contracts for a living and want playbooks inside Word. Skip it if you need a published price.
2. Revise: Best for AI redlines at a published price
- Free plan: Yes, daily AI limit
- Paid from: $8/mo
- Built-in AI: Revise Agent
Revise is a browser word processor whose AI agent proposes contract text edits as tracked changes you accept or reject. A counterparty’s Word tracked changes and comments import as suggestions and comment threads, and pending suggestions export back to Word as tracked changes. In our single-contract test, it flagged contradictions and incorrect dates in margin comments, and the exported .docx kept its formatting and the unresolved comments and tracked changes.
It is not a CLM and has no playbooks or clause library. It runs outside Word, and its revision history compares versions of one document rather than two separate files. The free plan has a daily AI limit, and paid plans start at $8 a month.
Pick it if you want AI-proposed redlines and a Word tracked-changes round trip without a sales call. Skip it if you need playbooks, a CLM, or to stay inside Word.
3. LegalOn: Best for playbooks and clause libraries
- Free plan: No public trial
- Paid from: Custom
- Built-in AI: LegalOn Assistant
LegalOn reviews contracts against attorney-built playbooks and a clause library, on the web and in a Word add-in aimed at in-house legal, procurement, and law firms. Its AI Revise feature produces one-click redlines in Word’s native track changes.
Plans (Core Review, Contracting Suite, and Productivity Suite) are quoted on request.
Pick it if your team wants to review contracts against the same playbook. Skip it if you need published self-serve pricing or only document comparison.
4. Claude for Word: Best general AI assistant inside Word
- Free plan: No, Pro or higher
- Paid from: $20/mo
- Built-in AI: Claude
Claude for Word is Anthropic’s add-in for Word on Windows, Mac, and the web. It answers questions about the contract with citations to its sections, edits selections while keeping their formatting, works through comment threads, and summarizes a counterparty’s redlines. With Track Changes on, its edits arrive as native Word revisions.
It needs a Claude Pro plan or higher and does not run in Word 2016 or 2019 perpetual licenses. Anthropic’s page does not list legal playbooks.
Pick it if you already pay for Claude and redline in Word. Skip it if you want a free option.
5. Litera Compare: Best for multi-format and bulk blacklines
- Free plan: No public trial
- Paid from: Contact sales
- Built-in AI: Lito
Litera Compare produces what Litera calls deterministic redlines across Word, PDF, Excel, and PowerPoint, one-to-one, one-to-many, or in bulk. It runs on the desktop, in a browser, and on mobile, and connects to Microsoft 365, Google Workspace, iManage, NetDocuments, and SharePoint.
Its AI agent, Lito, analyzes the risk in a set of changes and suggests rewrites. Litera’s product page publishes no price or trial terms and offers a demo request.
Pick it if your firm runs on a document management system and compares many files. Skip it if you want a published price or trial terms before you contact the vendor.
6. Draftable: Best for comparison at a published price
- Free plan: Free web compare
- Paid from: $10.75/mo
- Built-in AI: None
Draftable has a free web compare that needs no signup and exports a PDF. The Business plan ($10.75 per user per month, billed annually) adds the Windows desktop app.
Redlines in Word with tracked changes, and integrations with Microsoft Office, iManage, and NetDocuments, need the Legal plan ($21.75 per user per month, billed annually). Draftable’s product pages do not list built-in AI.
Pick it if you need clear comparisons at a published price. Skip it if you want software to propose the edits.
7. Microsoft Word Compare: Best built-in blackline
- Free plan: Word for the web (Compare documented for desktop only)
- Paid from: $9.99/mo
- Built-in AI: Copilot
Word already has a comparison tool. Under Review > Compare, the legal blackline option creates a third document that shows the differences between two versions as tracked changes. Microsoft documents it for Word for Microsoft 365, 2024, and 2021 but not for the free Word for the web in the table above.
Copilot in Word can draft and rewrite, but in our test it edited text directly with a blue highlight and an undo button rather than as tracked changes.
Pick it if you already have desktop Word and need an occasional comparison. Skip it if you need comparisons across PDFs and other formats, or in bulk.
8. Ironclad: Best for redlining inside a CLM
- Free plan: No public trial
- Paid from: Custom
- Built-in AI: Jurist
Ironclad is a contract lifecycle management platform. Its AI redlines a full contract against your playbook as tracked changes, and its Jurist add-in for Word drafts, redlines, and analyzes risk grounded in your playbooks.
Pricing is custom. A CLM is a larger purchase than a redlining tool, so it makes most sense when the rest of the contract process is part of the decision too.
Pick it if your legal team is choosing a CLM anyway. Skip it if you only need redlines.
Which tool fits your job?
The right tool depends on the task. If you need to compare versions, use a blackline tool. If you need edits proposed, use an AI tool, with or without playbooks. A CLM fits when the purchase covers the whole contract process.
| The job | Best fit | When manual Word still wins |
|---|---|---|
| AI review against your firm's positions | Spellbook or LegalOn | Each contract is different and a playbook would not apply. |
| AI-proposed redlines at a published price | Revise or Claude for Word | The contract is short and you know exactly what to change. |
| Blacklines across Word, PDF, and document systems | Litera Compare | You compare two Word files now and then. |
| Low-cost comparisons | Draftable | Word's built-in Compare covers your files. |
| An occasional blackline | Microsoft Word Compare | This is the manual workflow. |
| Redlining as part of a contract system | Ironclad | You handle few contracts and need no approval workflow. |
What plain Word still does best
- Native tracked changes. Counterparties already using Word can review them without another redlining product.
- Compare is built in. The legal blackline option covers the basic comparison job in desktop Word.
- Many add-ins run in it. Spellbook, Claude, LegalOn, Ironclad, Juro, SpotDraft, Harvey, and Ivo all work in Word.
If your workflow ends in Word, check the exported tracked changes and formatting before you send a redline, whichever tool made it.
What each tool costs
Four of the eight tools publish a list price. They are Revise, Draftable, Claude for Word (through Claude Pro), and Word (through Microsoft 365). Spellbook, LegalOn, and Ironclad use custom pricing, and Litera Compare’s product page publishes no list price. For Draftable, Word redlines need the Legal plan ($21.75 per user per month, billed annually), not the Business plan shown below.
| Tool | Cheapest paid plan | Monthly | Per year | AI on that plan |
|---|---|---|---|---|
| Spellbook | Custom, priced per team | Custom | - | Contract review, drafting, and redlines |
| Revise | Plus (or $72/yr billed annually) | $8/mo | $72 | Monthly AI limit, no daily limit. GPT-6 Sol, GPT-6 Astra, and Claude Opus 5.5 need Pro |
| LegalOn | Custom | Custom | - | Core Review plan, price not disclosed |
| Claude for Word | Claude Pro (or $17/mo billed annually) | $20/mo | $200 | Included in Pro |
| Litera Compare | Custom | Contact sales | - | Not disclosed |
| Draftable | Business (per user, billed annually) | $10.75/mo | $129 | None |
| Microsoft Word | Microsoft 365 Personal | $9.99/mo | $99.99 | Eligible Microsoft 365 plans, with limits. Personal/Family AI benefits are for the owner |
| Ironclad | Custom | Custom | - | Not disclosed |
How to pilot a redlining tool
- Use a copy of a contract you have already negotiated, so you know what a good redline looks like.
- Give it your positions as a playbook in tools that support one, or as a written checklist in the prompt.
- Inspect every change before accepting it, and check who each tracked change is attributed to.
- Open the exported file in Word and confirm that numbering, comments, and tracked changes came through.
- Run Word’s Compare against the version you last sent, to catch any change made without tracking.
- Read the vendor’s security and data terms before uploading client documents.
The bottom line
For version comparison, use Word, Draftable, or Litera Compare. For playbook review, use a legal AI product such as Spellbook or LegalOn. For AI-proposed redlines at a published price, Claude for Word works inside Word and Revise works in the browser. Choose a CLM only when storage and approvals are part of the purchase.
Sources
Prices and plan details were checked against each vendor’s own pages on October 4, 2026. Prices are in US dollars as each vendor lists them, and some include local tax. Vendors change plans often, so confirm on the linked page before you buy.
- Spellbook: Pricing, Spellbook
- Revise: Pricing, Supported models, Agent capabilities, Word compatibility, Import and export, MCP server, Suggesting mode, AI usage limits
- LegalOn: Pricing, LegalOn in Word, AI Revise in Word
- Claude for Word: Claude for Word, Pricing
- Litera Compare: Litera Compare, Product sheet
- Draftable: Pricing, Online compare
- Microsoft Word: AI capabilities and access, Previous versions, Track Changes, Navigation pane, Real-time co-authoring, Save as PDF, Compare documents (legal blackline), Microsoft 365 plans, Word for the web, Revise's AI review test, Copilot in Word, Track Changes in Word for the web, Word options: General, Print a document, Office for the web in OneDrive, Microsoft 365 mobile apps, Removed Windows features (WordPad), Word for the web service description, Similarity checking, Editing with Copilot and Track Changes (Microsoft 365 Copilot), Copilot and document length, When you need a Microsoft 365 subscription
- Ironclad: Pricing, AI Assist, Jurist for Word
- Juro: Pricing, Word add-in, Product updates, March 2026
- SpotDraft: Pricing, VerifAI, Word desktop integration
- Harvey: Harvey, Harvey agents in Word, Document-wide edits in Word
