Introduction
Grammarly is best known as the market leader for grammar and spelling. Recently, Grammarly expanded its suite to include more advanced tools: an AI detector, an AI humanizer, an AI essay grader, an AI chat feature, and more.
For this review, we’ll focus only on Grammarly’s AI detector and AI humanizer.
🔎 What Grammarly Offers
Grammarly’s offering is large, but here’s what’s relevant:
- AI Detector → Detects whether a text is written by AI.
- AI Humanizer → Rewrites AI-generated content into more human-like text.
- Grammar Checker → Core product that built Grammarly’s brand.
- AI Essay Grader → Automated scoring and feedback.
- AI Chat → Drafting, editing, and assistance features.
💰 Pricing
Grammarly positions itself as a premium platform:
- $30 per month → Standard monthly plan.
- $12 per month (billed annually) → Discounted yearly subscription.
- Enterprise contracts → Available for teams, schools, and organizations.
🖥 User Experience
Grammarly’s UX remains one of the best on the market:
- Fast & polished → Results load instantly, edits are seamless.
- Cross-platform → Works on web, desktop, mobile, and as a browser extension.
- Integrated workflow → Users can switch between grammar, plagiarism, and AI detection in one place.
📊 Performance Testing
We tested Grammarly’s AI detector with four text types:
- GPT-5 text
- Human text
- Grammarly humanized
- TwainGPT humanized
| GPT-5 Text | Human Text | Grammarly | TwainGPT |
|---|---|---|---|
| 66% AI | 0% AI | 66% AI | 0% AI |
Results:
- Grammarly flagged GPT-5 output as 66% AI.
- Human text was flagged correctly as 0% AI.
- Grammarly’s AI humanizer failed, with its output still flagged as 66% AI.
- TwainGPT bypassed Grammarly, scoring 0% AI.
✅ Pros and ❌ Cons
Pros
- Decent AI detector
- Industry-leading editing and grammar tools
- Clean and fast user interface
Cons
- Expensive pricing ($30/month or $12/yearly)
- Weak AI humanizer that doesn’t bypass detectors
- Limited transparency compared to tools like GPTZero
🏁 Final Verdict
Grammarly includes a decent AI detector within one of the most popular editing platforms in the world. Its detection is fairly accurate, and its grammar, style, and clarity tools remain unmatched.
But Grammarly’s AI humanizer is weak. It doesn’t bypass AI detectors and likely wasn’t designed to. This makes it ineffective if the goal is to avoid detection.
For clean, polished writing and reliable detection, Grammarly delivers. But for consistently bypassing AI detectors, TwainGPT is the best choice on the market.
✅ Bypass Grammarly with TwainGPT: Try TwainGPT