AIWriteBook vs Merlin AI
Plans, free access, limits and intended use side by side, taken from each vendor’s own pages. No score and no winner: the facts show where the two differ.
Change tools
Plan, write, edit, format and publish a book with AI, with a cover and audiobook on higher plans
Read the fair use terms before you buy a year of Pro
- Free access
- AIWriteBook: Free access
- Merlin AI: Free access
- Paid from
- AIWriteBook: USD 20 per month
- Merlin AI: USD 15 per seat a month
- Plans listed
- AIWriteBook: 5
- Merlin AI: 3
- Public API
- AIWriteBook: Not confirmed
- Merlin AI: Not confirmed
Where AIWriteBook and Merlin AI differ
- PlansAIWriteBook lists 5 plans and Merlin AI lists 3.
Head to head
Each value from the tool’s profile and the vendor’s own pages
| AIWriteBook | Fact | Merlin AI |
|---|---|---|
| Access and price | ||
| Free access availableFree · USD 0 | Free accessSame | Free access availableMerlin Free · USD 0 |
| USD 20 per monthPlus · or $12 per month billed yearly · $144 a year | Lowest listed paid plan | USD 15 per seat a monthMerlin Teams · billed $180 yearly |
| Free plan (100 credits); paid from $12 a month billed yearly | Pricing model | Free $0; Pro $19 a month, billed yearly |
| 5 | Plans listedDiffers | 3 |
| Not confirmed | Public API | Not confirmed |
| Not confirmed | Card to start | Not confirmed |
| Not confirmed | Open source | Not confirmed |
| What it is for | ||
| Self-publishing authors, ghostwriters and non-fiction writers who want one place to outline, draft in their own style, edit and prepare a book for Amazon KDP | Built for | Trying several AI models from one account, mainly through a browser extension |
| Writing & content | CategorySame | Writing & content |
| Platforms |
|
| Works with |
|
| How current | ||
| Profile sources checked | ||
| Prices confirmed · Oct 17, 2026 | Pricing checkSame | Prices confirmed · Oct 2, 2026 |
Official source check for both tools. No hands-on testing and no score: “Differs” marks a documented difference, not a better tool.
Plans and prices
AIWriteBook
Prices confirmed · Oct 17, 2026- FreeUSD 0
- PlusUSD 20 per monthor $12 per month billed yearly · $144 a year
- ProUSD 50 per monthor $30 per month billed yearly · $360 a year
- UltraUSD 200 per monthor $120 per month billed yearly
- One-time creditsUSD 20 for 250 creditsor $50 for 2,000 credits
Merlin AI
Prices confirmed · Oct 2, 2026- Merlin FreeUSD 0
- Merlin ProUSD 19 a monthbilled $228 yearly
- Merlin TeamsUSD 15 per seat a monthbilled $180 yearly
Strengths and limits
AIWriteBook
Strengths
- Free plan with no card: The pricing FAQ says you can plan a full book and get a first chapter free, with no credit card required.
- Content stays yours: The terms say you keep ownership and commercial rights to what you create, and the privacy policy says your content is not used to train its models or by its AI providers.
- Credit costs are published: The terms list per-action credit costs, so you can estimate a book before paying.
Limits to plan around
- Pages disagree on credit expiry: The pricing FAQ says unused subscription credits expire after a month, while the terms say Pro credits roll over for up to 3 months.
- Audiobooks are credit-heavy: At the terms' rate a 2,000-word chapter costs about 880 credits, so a full audiobook can outrun a plan's monthly allowance.
- Refunds are narrow: The terms allow a refund only within 7 days of the first subscription purchase and with under 50% of credits used; renewals and one-time credit packs are non-refundable.
Merlin AI
Strengths
- Several model families in one account: The pricing page lists models from OpenAI, Anthropic, Google, DeepSeek and xAI, so you can compare answers without separate sign-ins.
- Works where you already browse: The Chrome extension offers summarizing and writing on the page you are viewing, alongside web, desktop and mobile apps.
- A Free plan to try first: Free costs $0 with limited access to basic and Plus-level models, so you can test before paying.
Limits to plan around
- Fair use limits sit behind unlimited: The terms end service for the rest of the month above $100 of usage cost and for the day above $16, and the plan table does not state this.
- Extension sends visit data: The privacy policy lists page URL, previous URL, referrer and user ID among data sent to Merlin's servers.
- No API and a 100k context: The pricing page says there is no direct API access and the Pro context window is currently 100k tokens.
See both products
Start from your task, not from a winner.
Run both tools on the same real task, then compare the result, how much editing it needs and how fast it uses your plan’s allowance.
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Comparing tools from different categories is fine, and often useful — a writing assistant and a research tool solve different halves of the same job. The table will show you exactly where they diverge.
Questions about comparing tools
How does the comparison work?
Add two tools to the comparison tray from any tool card, then open this page. The table pulls each tool's verified plan details, platforms, strengths and limits from its profile, so both columns carry the same kind of evidence, with a separate source-check date for each tool.
Do you declare a winner?
No. The table sets two tools against each other on documented facts, not on a score. Which one wins depends on your task, your budget and your usage volume — three things we cannot see from here.
Why are some cells empty or marked unverified?
Because we could not confirm that detail on the vendor's own pages. Rather than filling the gap with a figure from elsewhere, we mark it and say why on the tool's profile.
Can I compare more than two tools?
Not at once. Two columns keep the differences readable and force a real decision. Remove either selected tool to replace it, or clear both to start a new pair.
Every figure in the table above comes from the linked profile, where the source and the verification date are listed. Browse all tools or read the editorial policy.