ProWritingAid vs Grammarly: Which Editor Fits a Book?

The short version

• For a novel or other long manuscript: ProWritingAid. It has fiction reports on pacing, overused words and sensory detail, a Chapter Critique, and it works inside Scrivener and Atticus as well as Word and Google Docs.
• For everything you type, on every device: Grammarly. It runs on Windows, Mac, the web, iOS and Android, with browser extensions for Chrome, Safari, Firefox and Edge.
• For the lowest yearly price: ProWritingAid Premium at $120 a year, against $144 for Grammarly Pro. ProWritingAid also sells a lifetime licence; Grammarly does not.

On the BookBird Author Score, ProWritingAid leads 8.8 to 8.1. Both earn full Cost points for their free plans. ProWritingAid confirms all seven editing jobs on our list, including fiction reports and a statement that your writing is not used to train AI; Grammarly confirms five, and its own trust page says it uses your text to improve its models unless you opt out. Grammarly’s far higher search interest narrows the gap.

ProWritingAid vs Grammarly, side by side

Prices in USD as shown on each vendor’s site on October 7, 2026.

Price: the same month, a different year

Paid by the month, the two are level: ProWritingAid Premium and Grammarly Pro both cost $30. The difference shows up on longer billing. ProWritingAid Premium is $120 a year ($10 a month), and Premium Pro is $144 a year. Grammarly Pro is $60 a quarter or $144 a year. So a year of ProWritingAid’s basic paid plan costs $24 less than a year of Grammarly Pro, and its top plan costs the same.

ProWritingAid is the only one of the two with a lifetime licence: $399 for Premium or $699 for Premium Pro, paid once. The $399 Premium licence costs less than three years of Grammarly Pro at $144 a year, which comes to $432. ProWritingAid offers a 3-day money-back guarantee on its yearly and lifetime plans. Grammarly offers a 7-day trial of Pro. Grammarly also has an Enterprise plan with custom pricing, which an author working alone will not need.

Free plans

Both free plans check spelling and grammar. ProWritingAid’s free plan checks 500 words at a time, which means pasting a chapter in pieces. Grammarly’s free plan includes 100 generative AI prompts a month, against 2,000 on Pro. If you only need a grammar pass on short texts such as blurbs, emails and social posts, either free plan will do; for a full manuscript, the 500-word limit is the one to plan around.

What each one checks

ProWritingAid: reports for fiction

Beyond grammar, spelling and punctuation, ProWritingAid lists more than 25 writing reports, including pacing, overused words, sensory detail and readability. Chapter Critique gives feedback on a chapter, Story Canvas gives feedback on a story idea, and a comparison feature measures your writing against 90 fiction authors. You can set up your own style guide and dictionary, which helps with invented names in fantasy and science fiction. It has a Rephrase tool for rewriting sentences.

It works inside Microsoft Word, Google Docs, Scrivener and Atticus. That matters for authors, because it means you can check a manuscript in the app you draft or format it in. See our book writing software comparison for Scrivener and Atticus themselves.

Grammarly: checks everywhere

Grammarly covers spelling and grammar correction, tone detection and adjustment, full-sentence rewrites and fluency suggestions. It also lists plagiarism and AI-generated text detection, and citation consistency, which ProWritingAid’s feature list in our data does not mention. Its generative AI prompts can draft or rewrite text on request.

Its strength is reach. Grammarly runs on Windows, Mac, the web, iOS and Android, integrates with Google Docs and Microsoft Office, and has extensions for the four main browsers. If much of your writing happens on a phone or in a browser, from newsletters to Amazon author pages, it follows you there.

What neither one replaces

Neither tool replaces a human editor. Both flag issues and suggest fixes, and the judgement on structure, plot and character stays with you or the editor you hire. Our guide to copy editing vs proofreading explains which stage of editing software can cover and which needs a person.

Platforms and where they run

Grammarly is listed for Windows, Mac, the web, iOS and Android, plus a browser extension. ProWritingAid is listed for the web, Windows, Mac and a browser extension, with no mobile apps in the data we collected. Platforms are not part of the score; they are a filter on our editing software list, where you can narrow it to the devices you write on.

Search interest

Grammarly is searched about 2,740,000 times a month in the US and ProWritingAid about 18,100 (Google Ads data via DataForSEO). That gives Grammarly the full 20 Adoption points and ProWritingAid 13.5. Search interest measures how widely a tool is used, not how well it edits a novel.

Which one should an author choose?

Choose ProWritingAid if your main job is editing a book-length manuscript, especially fiction. The reports are built around the problems novelists look for, it plugs into Scrivener and Atticus, it costs less per year, and you can buy it once.

Choose Grammarly if you need checks across many short texts and devices, if you want plagiarism detection, or if you write on your phone.

Some authors use both: Grammarly’s free plan for everyday writing and ProWritingAid for the manuscript. For a free check of readability and passive voice before you pay for either, Hemingway Editor’s free online editor is in the table below, and our guide to active vs passive voice explains what it is flagging.

Other editing software we score

Hemingway Editor focuses on readability: it grades text, highlights wordy sentences and passive voice, and lets you set a target reading level. Its free online editor costs nothing, and the desktop app costs $19.99 once. AutoCrit is a fiction-focused online editor that compares a manuscript against major genres and includes a Story Analyzer for character arcs and plot threads.

Questions