7 Best Contract Redlining Tools

Contract redlining tools mark up a draft so both sides can see every proposed change. The right pick depends on where your contracts live: Word, Google Docs, PDF or an AI assistant inside Word.

Each tool below shows proposed changes clearly enough to work from. Someone still has to decide which position to take.

Arceus Legal publishes this site and is ranked #1 below; we've aimed to describe every other pick fairly and tell you when one of them fits better.

Key Takeaways

• Word's Track Changes and legal blackline Compare handle most markups for Microsoft 365 teams.
• Draftable compares two versions when a counterparty edits without tracking.
• Google Docs Suggesting mode suits internal edits and exports as tracked changes.
• Spellbook and LegalOn suggest AI redlines in Word for a lawyer to approve.
• Arceus Legal is a service: a licensed attorney approves every redline we return.

At a glance

What a redlining tool does

A redlining tool records each insertion, deletion and comment against the prior draft. The other side then accepts or rejects each change.

Most tools handle one of two separate jobs. Tracking records each edit while you make it. Comparison builds a redline after the fact by matching two versions.

Teams need both covered, because a counterparty can turn tracking off, edit a clause and return a clean-looking file. Our position: run a compare on every returned draft, even one full of tracked changes.

Our guide on how to redline a contract in 9 steps covers the markup itself.

How to evaluate a redlining tool

Everything below is current as of October 2026. We judged each pick on format fit, compare quality, playbook support, who approves the output and published price. Before you buy one, ask these five questions.

1. 1.Does it open and return your counterparty's format? Mismatched formats add friction on every turn.
2. 2.Can it compare versions sent without tracking? If not, it'll miss unflagged edits.
3. 3.Can it apply your fallback positions? Without a playbook, each reviewer starts from scratch.
4. 4.Who approves the final markup? Software suggests edits, and a person owns each call.
5. 5.Is the price public? A quote-based price usually means a sales cycle before testing.

Best for Microsoft Word

2. Microsoft Word: Best for Track Changes and legal blackline

Most counterparties send contracts as Word files, so Microsoft Word is the natural starting point. Its Track Changes and Compare features cover core redline work without extra software.

Track Changes records every insertion and deletion by author. On desktop, Lock Tracking uses a password to keep others from switching tracking off.

Compare is the feature many busy teams tend to skip. Under Review, it builds a legal blackline as a new third document, and the two source files stay unchanged.

Key features:

• Track Changes for everyone or for your own edits
• Lock Tracking with a password on desktop
• Legal blackline Compare that leaves both originals untouched
• Accept or reject one change at a time, or all at once
• Track Changes in Word for the web, iPad and iPhone

Pricing: Desktop Word comes with Microsoft 365 Apps for business at $10.00 per user per month, paid yearly.

Who should choose Microsoft Word:

• Teams whose counterparties send Word files
• Anyone who needs a blackline without buying separate software

Limitations: Microsoft documents Compare for desktop Word, and Word offers no playbook or guidance on which edits to accept.

Microsoft Word vs Arceus Legal

Word gives you the markup tools, and someone on your team still decides each position. Arceus Legal returns the finished redline with a licensed attorney's approval.

3. Draftable: Best for comparing two versions

Draftable is document comparison software built for legal teams. It turns two versions of a contract into a redline, which helps when a counterparty edits without tracking.

Draftable says 1,300+ law firms and legal teams use it. Compare shows changes side by side in Word, PDF, PowerPoint and Excel files. Its legal plan adds redline output, including Outlook email comparison.

The legal plan adds profiles that lock comparison settings, which keeps output consistent across a team.

There's also a free web-based comparison tool that needs no signup. It accepts PDF, Word, Excel, PowerPoint and plain text files.

Key features:

• Side-by-side comparison of Word and PDF files
• Redline export to Word, PDF, Excel and PowerPoint on the legal plan
• Outlook email comparison on the legal plan
• Integrations with iManage, NetDocuments and SharePoint

Pricing: Draftable Compare costs US$129 per user per year for enterprise teams and US$261 for law firms and legal teams, billed annually.

Who should choose Draftable:

• Legal teams that compare versions daily
• Law firms working from iManage or NetDocuments

Limitations: The desktop app runs on Windows, with Mac support listed for late 2027. It shows differences but doesn't suggest which position to take.

Draftable vs Arceus Legal

Draftable shows exactly what changed between two drafts of a contract. Arceus Legal decides what to do about each change, with an attorney approving the redline.

Best for Google Docs

4. Google Docs: Best for internal edits in Suggesting mode

Google Docs is a browser-based word processor with a Suggesting mode that works like Track Changes. It's the easiest way to get a whole deal team editing one draft.

Switch from Editing to Suggesting and your edits appear in color, with deletions crossed out. The owner accepts or rejects each suggestion, or all of them under Tools.

Google says Office tracked changes become suggestions on conversion, and suggestions become tracked changes on export. Compare documents under Tools builds a new doc showing differences as suggestions.

Key features:

• Suggesting mode with accept and reject on each change
• Accept all or reject all from Tools
• Compare documents, with differences credited to a name you choose
• Word tracked changes convert into suggestions

Pricing: Anyone with a Google Account can create in Docs. Google Workspace Business Starter lists at $7.00 per user per month.

Who should choose Google Docs:

• Teams with several internal reviewers on one draft
• Sales and RevOps teams that work in Google Workspace

Limitations: Docs has no clause guidance or playbook, and most counterparties expect a Word file back.

Google Docs vs Arceus Legal

Google Docs is where your team agrees on what it wants. Arceus Legal is where an attorney checks whether those edits protect you.

Best for PDF redlining

5. Adobe Acrobat Pro: Best for PDF markup and compare

Adobe Acrobat Pro is PDF software that compares two PDF versions. It also lets reviewers comment on a file they can't edit directly.

Acrobat's Compare Files tool finds changes to text, images, headers and footers, formatting and annotations. It then summarizes what was replaced, inserted or deleted.

That matters when a counterparty sends a signature-ready PDF that should match the agreed Word draft. Compare the two files before anyone on either side signs.

Acrobat Reader is listed for viewing and comments, and its feature list doesn't include comparison.

Key features:

• Compare Files for two PDF versions, side by side or single page
• Filters for text, images, formatting and annotations
• Summary of replaced, inserted and deleted items
• Comment and markup tools for PDFs you can't edit

Pricing: Acrobat Pro for teams costs US$23.99 per license per month, annual and billed monthly. Acrobat Standard for teams is US$16.99 but lacks Compare.

Who should choose Adobe Acrobat Pro:

• Teams that receive contracts as PDFs
• Signers who want a final check before execution

Limitations: PDF markup is awkward for a long negotiation, so the back and forth tends to move back to Word.

Adobe Acrobat Pro vs Arceus Legal

Acrobat confirms the signature copy matches what you agreed. Arceus Legal helps you reach that agreement, with an attorney approving the terms.

Best for AI-assisted redlining

6. Spellbook: Best for AI redlines inside Word

Spellbook is AI contract review and drafting software that runs inside Microsoft Word. It suggests redlines as tracked changes for a lawyer to accept or reject.

Spellbook says 5,000+ legal teams use it, and it's designed for in-house teams and law firms. Its review feature redlines from your side, with every suggestion tracked.

Playbooks turn your team's standards into checklists applied on each review. Treat the output as a first pass that a lawyer confirms.

Its pricing page lists a Spellbook Suite that pairs the Word add-in with a product called Associate. Larger organizations can ask Spellbook about extended trial periods.

Key features:

• Word add-in, so review happens in the contract itself
• Redline suggestions inserted as tracked changes
• Playbooks that apply team standards on every review
• Drafting help alongside review
• Free trial before you commit to a seat count

Pricing: Spellbook's pricing page sets cost by team size and offers a 7-day free trial.

Who should choose Spellbook:

• In-house lawyers who redline in Word every day
• Law firms that want AI suggestions in their current workflow

Limitations: Spellbook is software built for lawyers and legal teams. A team without legal staff still needs someone qualified to approve its suggestions.

Spellbook vs Arceus Legal

Spellbook speeds up a lawyer who's already on your team, while Arceus Legal supplies the lawyer. Our Spellbook alternatives list covers other options worth comparing.

7. LegalOn: Best for AI review with prebuilt playbooks

LegalOn is AI contract review software that redlines contracts against playbooks. It works in its own platform or inside Word.

LegalOn advertises 135+ contract playbooks live on day one, described as attorney-built standards for NDAs, MSAs, DPAs and more. The company says 9,000+ legal teams use its software.

The software flags risk with citations and suggests edits. Every plan includes a Word add-in and web access, and higher tiers add custom playbooks.

The top tier adds matter management and intake from email, Slack and Microsoft Teams. LegalOn's pricing page says customer data isn't used to train third-party foundation models.

Key features:

• Prebuilt playbooks for common commercial contracts
• Redlines against your playbook, with risk citations
• Word add-in plus a web platform
• Custom playbooks on higher tiers

Pricing: LegalOn builds a quote from team size and features on its pricing page, with no dollar figures shown.

Who should choose LegalOn:

• In-house legal teams that want playbooks from the start
• Teams with enough volume to justify a platform

Limitations: LegalOn is software built for in-house legal teams. It suggests edits, and a lawyer on your side still owns each decision.

LegalOn vs Arceus Legal

LegalOn fits better when you have lawyers who want software for high volume. Arceus Legal fits teams that want the attorney work handled. Our LegalOn alternatives roundup covers other options worth comparing.

Best for teams that want the redline done for them

1. Arceus Legal: Best for teams that want the redline done for them

Arceus Legal is a service, not a tool. You send the contract, and our licensed attorneys return the redline.

Every tool above assumes someone on your side knows which position to take. We're built for teams without that person, or with one who's at capacity.

You send requests through Slack or email, and AI does the first pass. A licensed, US-barred attorney approves every output. Our product page shows how that workflow runs.

We connect to HubSpot, Salesforce and Gmail for deal context and predict close dates. Arceus Legal remembers each customer's positions. Your second MSA is reviewed against your first, with your preferences, risk tolerance and business goals accounted for.

We cover NDAs, MSAs, SOWs, DPAs, BAAs, vendor and customer contracts, and renewals. CounselOS adds a vault, e-signature and renewal tracking.

We had an urgent request and a set of redlines holding up a deal. Arceus didn't just send comments back. Their attorney got on two calls with the counterparty directly and we signed that week.

— Graham Gullans, CFO & Chief Strategy Officer, Modulate

Client experiences vary; past results don't guarantee future outcomes.

Key features:

• Slack and email intake
• AI first pass, with a licensed attorney approving every output
• Customer memory of the positions you took on past contracts
• Custom plan: dedicated attorney, custom legal playbook and reserved quarter-end capacity

Pricing: On-Demand NDA and order form review is $250, and standard review (1 to 24 pages) runs $500 to $1,000. Negotiation on the On-Demand plan starts at $500.

Standard contract reviews average 3 to 5 hours. We guarantee an 8 hour turnaround on qualifying standard contract reviews, or the review is free.

Who should choose Arceus Legal:

• Founders and sales teams without in-house counsel
• Lean legal teams needing quarter-end overflow help

Limitations: We're a service rather than a tool you run yourself, and we don't handle litigation, M&A, patents, immigration or tax.

Where tools stop and judgement starts

Software can show a change or suggest a fallback. Deciding whether a lower liability cap works for this customer takes judgement about deal size, bargaining power, renewal history and risk appetite.

Our view: for most growth-stage teams, written fallback positions matter more than the tool. Start with a contract playbook, and plain Word will carry you far.

For AI speed with a lawyer accountable for the output, see our list of AI contract review tools with licensed attorney sign-off.

Pricing compared

Prices come from each vendor's site and our pricing page, checked October 22, 2026.

Software is priced per seat, while our pricing is per document. Weigh both against your reviewer's hours on each redline.