| GPTinf | Grammarly AI Humanizer | |
|---|---|---|
| Starting price | $12/mo | $12/mo |
| Free tier | 200 words | 0 words |
| Bundled detector | No | No |
| Founded | 2023 | 2024 |
| Best for | Writers who want granular control over tone and which specific sentences get rewritten. | Professionals who want more natural-sounding AI-assisted drafts without a dedicated bypass-focused tool. |
Price: Grammarly AI Humanizer is cheaper to start, at $12/mo vs $12/mo.
GPTinf: From $12/mo, scaling with monthly word volume.
Grammarly AI Humanizer: Included in Grammarly Premium ($12/mo annual) and Business plans.
Free tier: GPTinf offers a more generous free tier (200 words).
If you just want to test either tool before paying, GPTinf's 200-word allowance gives you more room to evaluate quality.
Detection performance
GPTinf: Marketed as being trained directly against detector models rather than general paraphrasing, which independent testers cite as the reason its scores hold up on technical text.
Grammarly AI Humanizer: Grammarly is explicit that the feature is meant to improve natural tone rather than guarantee detector evasion, which sets it apart from bypass-first competitors.
AI detector included: Neither tool bundles a built-in detector — pair either with GPTZero or Originality.ai.
Strengths at a glance
GPTinf
- Eight distinct rewriting modes (Academic, Formal, Informal, Creative, Simple, Standard, Expand, Shorten)
- Freeze-keyword feature protects technical terms and proper nouns from being altered
- Selective, sentence-level rephrase instead of forcing a full rewrite
Grammarly AI Humanizer
- Built into an app most professionals already have installed (browser, desktop, Docs)
- Focuses on clarity and flow rather than aggressive detection evasion
- Backed by Grammarly's long-standing grammar and tone engine
Our verdict
Choose GPTinf if: writers who want granular control over tone and which specific sentences get rewritten. Choose Grammarly AI Humanizer if: professionals who want more natural-sounding ai-assisted drafts without a dedicated bypass-focused tool.