Grammarly
AI writing assistant trusted by 30 million daily users for grammar and clarity
What is Grammarly?
Grammarly is the most widely used AI writing assistant in the world, with 30 million daily active users and a browser extension that works across virtually every writing surface — Gmail, Google Docs, LinkedIn, Slack, WordPress, and more. The combination of ubiquity and effectiveness has made it the default grammar tool for professionals, students, and non-native English speakers alike.
The free tier catches grammar and spelling errors competently. Grammarly Pro (formerly called Premium) adds advanced suggestions for clarity, engagement, delivery tone, and vocabulary. The Tone Detector analyzes how your message will be perceived before you send it — invaluable for professional emails and performance reviews. GrammarlyGO (the generative AI feature) now allows one-click rewrites, paragraph generation, and response suggestions.
Grammarly Business adds team-level Style Guides — custom rules that ensure brand voice consistency across all team writing. This is the brand voice feature of Jasper implemented at the grammar layer rather than the generation layer. For organizations where employees write customer-facing communications, Grammarly Business ensures consistency without requiring a content creation tool. In July 2025, Grammarly acquired the AI email client Superhuman — also reviewed on this site — to expand into full inbox management.
Key Features
- Real-time grammar, spelling, and punctuation correction
- Tone Detector
- Clarity and conciseness suggestions
- Vocabulary enhancement
- Plagiarism detection (Pro)
- GrammarlyGO (generative AI rewrites and suggestions)
- Style Guides (Business plan)
- Browser extension (Chrome, Firefox, Safari, Edge)
- Desktop app for Windows and Mac
- Microsoft Word and Google Docs add-ins
Pros & Cons
Pros
- Works everywhere — browser extension covers Gmail, Slack, LinkedIn, docs, and more
- Free tier is genuinely useful for basic grammar and spelling
- Tone Detector helps calibrate email and professional communication tone
- 30 million daily users — the most battle-tested AI grammar tool
Cons
- Suggestions can be overzealous — sometimes flags correct informal writing
- Free plan lacks the advanced suggestions that make Pro worthwhile
- Pro at $12/mo is reasonable but pricier than LanguageTool ($5.83/mo)
- GrammarlyGO generative features are weaker than dedicated AI writing tools
Pricing
Model: Subscription
| Plan | Price | Key Limits |
|---|---|---|
| Free | $0/mo | Basic grammar and spelling checks, 100 AI prompts/mo |
| Pro | $12/mo | Advanced suggestions, tone, clarity, GrammarlyGO, 2,000 AI prompts/member/mo (renamed from Premium) |
| Business | $15/user/mo (3+ seats) | All Pro + Style Guides, analytics, SAML SSO |
| Enterprise | Custom (150+ seats) | Unlimited AI prompts, BYOK encryption, SCIM, audit logs, dedicated support |
Frequently Asked Questions
- Is Grammarly accurate?
- Grammarly is highly accurate for grammar and spelling. Style suggestions are good but sometimes flag intentional stylistic choices — you can ignore suggestions that do not fit your voice. It is not perfect on technical jargon, domain-specific language, or creative writing that intentionally breaks grammar rules.
- Is Grammarly safe to use with confidential documents?
- Grammarly processes text through its servers, which some users find concerning for confidential or privileged documents. Grammarly states it does not sell data and encrypts all transfers. For highly sensitive documents, using Microsoft Word's built-in grammar checker keeps text off external servers.
Go deeper
For the full ranked breakdown of Grammar & Editing tools, including pricing and use-case picks, read our guide: Best AI Grammar Checker Tools 2026: 7 Tools Tested and Compared.