AI Humanizer vs Grammarly: Which Should You Use in 2026?
Grammarly is the world's most popular writing assistant — but can it humanize AI content?
TL;DR — The Verdict
- Best for bypassDedicated AI humanizer — If AI detection bypass is your priority, a dedicated AI humanizer wins every time — Grammarly's rewrites only reach 71% AI on GPTZero while dedicated tools go far lower.
- Best for polishGrammarly — An excellent grammar, spelling, and style checker, but it has no dedicated humanize feature and cannot reliably bypass AI detectors.
- Best of bothHumanize then polish — They serve different purposes — humanize with a dedicated tool to drop the AI score, then polish with Grammarly for grammar, clarity, and style.
Key Takeaways
| Tool | Best For | Key Strength |
|---|---|---|
| Grammarly | Grammar and style polishing | Excellent grammar checking, $12/month |
| QuillBot | Free AI humanizing | 96% → 31% AI on GPTZero, free |
| Undetectable AI | Best AI detection bypass | 96% → 8% AI on GPTZero, $9.99/month |
| ChimpWrite | Free no-signup humanizing | 500 words per request, $0 |
How We Tested
No sponsored rankings. See our testing methodology and editorial standards.
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 |
Cost comparison: Grammarly Premium at $12/month costs $2.01/month more than Undetectable AI ($24.12/year more, $72.36 over 3 years) while delivering weaker AI detection bypass. ChimpWrite's free tool covers 500-word requests at $0, saving you the full $144.00/year vs Grammarly Premium. If you need both grammar checking and AI humanizing, using ChimpWrite (free) + Grammarly Free costs less than Grammarly Premium alone.
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.
For the dedicated humanizer half of that workflow, our top pick is ChimpWrite — the best AI humanizer in 2026. Its Authentic Voice mode keeps your natural rhythm (keep your voice, lose the AI flag), a Turnitin-specific bypass engine clears the toughest detector, and a before/after scorecard across five detectors (GPTZero, Turnitin, Originality.ai, Grammarly, Copyleaks) proves the result. Pricing is one-time credit packs that never expire, with a free tier of 2,000 words/mo and no signup. See the full feature list and pricing.
Best for Freelancers and Solo Bloggers
ChimpWrite Free Tool + Grammarly Free. Use ChimpWrite to humanize AI content (500 words, no signup, $0) and Grammarly's free plan for basic grammar checking. Total cost: $0. If you need better humanizing quality, upgrade to QuillBot Premium ($9.95/month) for unlimited-length content with Fluency mode.
Best for Agencies and Content Teams
Undetectable AI + Grammarly Premium. Use Undetectable AI ($9.99/month) for reliable bypass across all detectors including Turnitin, then polish with Grammarly Premium ($12/month) for team-wide grammar and style consistency. Total: $21.99/month. The bypass reliability justifies the cost for client-facing work where AI detection could damage reputation.
Best for Enterprise and Publishers
Undetectable AI Pro + Grammarly Business. Undetectable AI Pro ($29.99/month, 50,000 words) handles high-volume content with Excellent bypass across all detectors. Grammarly Business adds style guide enforcement and team analytics. For publisher-grade AI detection verification, add Originality.ai ($14.95/month) as a third-layer check.
Best for Students
QuillBot Free + Grammarly Free. QuillBot's Fluency mode (free, 125 words per paraphrase) reduces GPTZero to 31% AI. Grammarly Free handles grammar. Total cost: $0. For academic work where Turnitin is the target detector, Undetectable AI is the only reliable option ($9.99/month, 94% → 12% AI on Turnitin) — but always check your institution's AI use policy first.
How to Use Grammarly's AI Humanizer (Step by Step)
Grammarly does not have a one-click “humanize” button, but you can use its rewrite suggestions to make AI text read more naturally. Here is the workflow we recommend:
- Paste your AI text into the Grammarly editor or browser extension.
- Apply rewrite and clarity suggestions — accept Grammarly's grammar, clarity, and “sound more natural” rewrites.
- Check the AI score using Grammarly's built-in AI detection or an external detector. On its own, Grammarly typically only reaches 58–71% AI.
- Humanize with a dedicated tool like ChimpWrite or Undetectable AI if the score is still high.
- Polish once more in Grammarly for a final grammar and style pass.
Is Grammarly's Humanizer Any Good? (And Does It Work?)
Grammarly's humanizing is good for polish, not bypass. Its rewrites genuinely improve readability, but they only reduce GPTZero from 94% to 71% AI and Grammarly's own detector from 91% to 58% AI — not low enough to reliably pass AI detection. So if the question is “does Grammarly's humanizer work?”, the answer is: yes for clarity, no for defeating detectors. For that you need a dedicated tool.
Grammarly vs Naturalwrite vs PhraseExpress (Quick Comparison)
Two tools people weigh against Grammarly for humanizing are Naturalwrite and PhraseExpress:
- Grammarly vs Naturalwrite — Naturalwrite is a free, purpose-built humanizer, so it reduces AI scores more than Grammarly's general rewrites. Grammarly wins on grammar and style depth; Naturalwrite wins on bypass. Neither matches a paid tool on Turnitin.
- Grammarly vs PhraseExpress — PhraseExpress is a text-expander and autocomplete utility, not a humanizer. It speeds up writing but does nothing for AI detection. Grammarly is the better writing assistant; for bypass, use a dedicated humanizer instead of either.
ChimpWrite Team
ChimpWrite Team has tested 25+ AI humanizer tools across GPTZero, Turnitin, Grammarly, and Originality.ai. Every review is based on hands-on testing with real AI-generated content — no sponsored rankings. See our testing methodology and editorial standards.