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ProWritingAid vs Grammarly: which editing tool fits a book manuscript?

Both check grammar, spelling and style, and both have a free plan. ProWritingAid's pricing page is built around fiction writers, with chapter and manuscript critiques. Grammarly's is built around everyday writing across apps, with AI prompts for generating text. The deciding questions are how long your text is, whether you want story-level feedback, and how you prefer to pay.

How we wrote this: we drafted this page with AI assistance from the vendors' official pages, fetched on 2026-10-17, then checked each fact against those pages. We did not buy or test these tools hands-on, so this page does not judge the accuracy of either tool's suggestions. Prices and plans are as of Oct 2026 and change; check the official site before you buy. Listings are editorial. We are not affiliated with or endorsed by any tool named here.

Quick answer

You want to run style reports on a whole chapter or manuscript for free: ProWritingAid's free plan checks 500 words at a time. Grammarly's pricing page does not list a word limit, but its free plan covers corrections and tone, not full-sentence rewrites.
You want story-level feedback (plot, characters, pacing): ProWritingAid lists Chapter Critique and paid Story Credit analyses such as Manuscript Analysis and Virtual Beta Reader. Grammarly's pricing page lists no fiction-specific feature.
You'd rather pay once: ProWritingAid sells lifetime licences. Grammarly's page data lists monthly, quarterly and annual plans, and no one-time price.
You write in many apps and on your phone: Grammarly lists apps for Windows, Mac, iPhone, iPad and Android, plus browser and Office extensions. ProWritingAid lists Google Docs, Microsoft Office, a desktop app and browser integrations.

Plans and pricing (as of Oct 2026, USD)

	ProWritingAid	Grammarly
Free plan	Yes. Grammar, spelling and punctuation; each line-editing report up to 2 runs a day on 500 words of text; 10 Rephrases a day.	Yes. Corrections ("write without mistakes"), tone detection and 100 AI prompts a month.
Main paid plan	Premium: $30/month billed monthly, or $10/month billed yearly ($120 a year), or $399 one-time (lifetime).	Pro: the plans page shows "$12 USD", with no billing period in its visible text. Plan data embedded in the same page lists Pro at $144 a year (annual), $60 every 3 months (quarterly) or $30 a month (monthly); $144 a year works out to $12 a month.
Higher plan	Premium Pro: $36/month billed monthly, or $12/month billed yearly ($144 a year), or $699 one-time. Adds more critiques and a writer community with live workshops.	Enterprise: contact sales. Aimed at organizations.
Paid features listed	Unlimited line-editing report runs on any length of document, 25+ writing analysis reports, unlimited Rephrases, custom style guide, Chapter Critique (1 a day on Premium, 30 on Premium Pro), discounts on Story Credits.	Full-sentence rewrites, tone adjustment, fluency help, unlimited personalized suggestions, plagiarism and AI-text detection, 2,000 AI prompts per member a month.
Extra paid add-ons	Story Credits for Manuscript Analysis, Virtual Beta Reader, Character Analysis, Plot Analysis and Marketability Analysis. Free users can buy them too.	None listed on the pricing page.
Trial and refunds	Yearly and lifetime plans: refund on request within 3 days of purchase. Monthly plans: no refunds. Story Credits are non-refundable.	Pro has a free trial, with an email reminder 2 days before it ends. The trial length isn't stated on the pricing page.
Languages	English only (US, UK, Australian and Canadian English).	Not stated on the pricing page; Pro lists "write fluently in English".
More than one computer	Licences are per person; one user may install on several computers.	Not stated on the pricing page.

Grammarly's page shows only "$12 USD" as visible text for Pro; the $144, $60 and $30 figures come from plan data embedded in the same page, as of 2026-10-17. The page doesn't say whether tax is included, and the price at checkout can differ. Check Grammarly's site and checkout screen before you buy.

Where ProWritingAid is the stronger fit

ProWritingAid is the one of the two that lists features made for long fiction: chapter critiques, plot and character analyses, and a virtual beta reader, plus reports on overused and repeated words across a document. If you edit your own novel and want a report-by-report pass, its paid plans remove the 500-word limit. It is also the only one of the two with a one-time lifetime price. Note the short refund window: 3 days for yearly and lifetime plans, and none for monthly plans.

Where Grammarly is the stronger fit

Grammarly is aimed at writing everywhere: it lists desktop apps, browser extensions for Chrome, Safari, Firefox and Edge, Microsoft Office and Google Docs add-ons, and mobile apps. That suits authors who want the same checks on emails, newsletters and ad copy as on the book. Its paid plan adds AI rewriting and generation (2,000 prompts per member a month) and plagiarism and AI-text detection, which ProWritingAid's pricing page does not list.

What neither page told us

How accurate either tool's suggestions are on fiction, especially dialogue and deliberate style choices. Try both free plans on the same chapter.
Grammarly's word limits on the free plan, and its trial length.

Sources

Every fact above comes from the vendor's own website. Link checked 2026-10-17.