Both tools catch grammar errors. That's where the similarity ends. They're targeting different types of writers — and understanding that difference makes the choice obvious once you know which one describes you.
Grammarly was built around everyday professional writing: emails, Slack messages, reports, social media, documents. It lives in your browser and integrates everywhere — Gmail, Google Docs, Notion, LinkedIn, Slack, Word. It catches errors as you type, in real time, without you having to think about it.
The AI rewrite suggestions ("improve clarity," "fix tone") are particularly useful for business writing because they preserve your meaning while removing wordiness and awkward phrasing. Grammarly Business adds tone detection across your team and brand voice settings.
ProWritingAid was built for writers working in documents — fiction, non-fiction, screenwriting, academic papers. It runs deep analysis across your entire document: overused words, passive voice percentage, dialogue tags, sentence length variation, pacing, repeated phrases, consistency issues.
The Reports feature is where ProWritingAid earns its reputation. Run a "Summary Report" on a chapter and you get a dashboard showing grammar issues, style problems, overused words, readability score, sentence structure distribution, and more — all at once. There's nothing like it in Grammarly.
| Feature | Grammarly | ProWritingAid |
|---|---|---|
| Real-time grammar correction | ✅ Excellent (in-browser, everywhere) | Good (in-app primarily) |
| Browser integration | ✅ Everywhere (Gmail, Docs, Slack, LinkedIn) | Limited (Chrome extension for basic check) |
| AI rewrites | ✅ Strong (sentence and paragraph level) | Good (sentence level) |
| Long-form document analysis | Basic | ✅ Exceptional (20+ report types) |
| Style and pacing feedback | Limited | ✅ Detailed (sentence variation, passive voice, clichés) |
| Word processing integration | Word, Google Docs | ✅ Word, Scrivener, Google Docs, Final Draft |
| Price (annual) | $144/year ($12/month) | ✅ $79/year ($6.58/month) — or lifetime $399 |
| Free tier | ✅ Basic grammar (quite useful) | Limited (3,000 word cap) |
Grammarly Premium costs $144/year. ProWritingAid Premium costs $79/year — 45% cheaper. ProWritingAid also offers a lifetime license for $399, which pays for itself in under 3 years. For freelancers and authors who write full-time, the lifetime plan is usually the right call.
Grammarly Business (for teams) costs $15/user/month ($180/year). If you have a 5-person writing team, that's $900/year for Grammarly vs $395/year for ProWritingAid team plans. The gap compounds at scale.
Both tools have added AI writing assistance in the last 18 months, but with different approaches.
Grammarly Go (AI generation): Can generate emails, rewrite entire paragraphs, adjust tone for different audiences, summarize documents. The quality is solid for professional writing — not at the level of Claude or ChatGPT, but useful for quick business communications when you don't want to switch apps.
ProWritingAid Rephrase (AI): Focused on sentence-level rewrites to improve clarity and style. More limited scope than Grammarly Go, but well-integrated into the document workflow.
If you need AI generation (not just editing), Grammarly Go has the edge. If you're a serious writer who uses Claude or ChatGPT for generation anyway, ProWritingAid's editing depth matters more than its AI generation.
Yes, and some writers do. ProWritingAid as the deep-edit tool for documents + Grammarly's browser extension for email and everyday comms. The cost of both is ~$220/year — still less than Grammarly Business for a small team.
That said, for most people, pick one and use it consistently. The best writing tool is the one you actually run on your work before it ships.
The free tier catches real grammar errors and includes basic suggestions — genuinely useful even before you pay.
Start with Grammarly Free →I earn a commission if you upgrade to Grammarly Premium.