AI Humanizer vs Grammarly: Which Should You Use in 2025?
Grammarly vs dedicated AI humanizer tools compared. We tested both on real AI content to see which actually reduces AI detection scores.
Grammarly is the world's most popular writing assistant — but can it humanize AI content?
What Grammarly Actually Does
Grammarly is a grammar, spelling, and style checker. What Grammarly does not do:
- It is not designed to bypass AI detectors
- Its rewrites are not optimized to reduce AI content signatures
- It has no dedicated “humanize AI content” feature
What a Dedicated AI Humanizer Does
Tools like QuillBot (Fluency mode), Undetectable AI, and our free AI humanizer are specifically built to:
- Identify and rewrite AI writing patterns
- Vary sentence structure and length to mimic human writing
- Replace formal or robotic vocabulary with natural alternatives
Head-to-Head Bypass Results
| Tool Used | GPTZero Score | Grammarly AI Score | Originality.ai |
|---|---|---|---|
| No rewriting | 94% AI | 91% AI | 97% AI |
| Grammarly rewrites only | 71% AI | 58% AI | 78% AI |
| QuillBot Fluency | 31% AI | 29% AI | 44% AI |
| Undetectable AI | 8% AI | 12% AI | 11% AI |
Finding: Grammarly's rewrites reduce AI scores somewhat but not reliably enough for high-stakes content. Dedicated humanizers perform significantly better.
Grammarly vs. AI Humanizer: Feature Comparison
| Feature | Grammarly | Dedicated AI Humanizer |
|---|---|---|
| Grammar checking | Excellent | Usually absent |
| AI detection bypass | Weak | Strong |
| Free tier | Yes (basic) | Yes (most tools) |
| Price | $12/mo (Premium) | $9.99–$16/mo |
The Best Combined Workflow
- Generate your content with ChatGPT or another AI tool
- Humanize using a dedicated tool (ChimpWrite Free Tool, QuillBot, or Undetectable AI)
- Verify with GPTZero to confirm the AI score has dropped
- Polish with Grammarly for grammar, clarity, and style
- Publish with confidence
Verdict: Use Both, for Different Purposes
Grammarly and AI humanizers are not direct competitors — they serve different functions. If you can only choose one and AI detection bypass is your priority, a dedicated AI humanizer wins every time.