| StealthGPT | Grammarly AI Humanizer | |
|---|---|---|
| Starting price | $14.99/mo | $12/mo |
| Free tier | 0 words | 0 words |
| Bundled detector | No | No |
| Founded | 2023 | 2024 |
| Best for | Long-form academic or research writing where sentence-level restructuring matters more than speed. | 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 $14.99/mo.
StealthGPT: Plans from $14.99/mo; per-word bundles available for one-off use.
Grammarly AI Humanizer: Included in Grammarly Premium ($12/mo annual) and Business plans.
Free tier: StealthGPT offers a more generous free tier (0 words).
If you just want to test either tool before paying, StealthGPT's 0-word allowance gives you more room to evaluate quality.
Detection performance
StealthGPT: Positioned and marketed specifically around Turnitin's originality algorithm rather than general-purpose detectors.
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
StealthGPT
- Generates and rewrites in one pass, so you can skip a separate AI writer
- Aggressive sentence-level restructuring rather than word substitution
- No word cap on paid plans — good for full-length papers
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 StealthGPT if: long-form academic or research writing where sentence-level restructuring matters more than speed. Choose Grammarly AI Humanizer if: professionals who want more natural-sounding ai-assisted drafts without a dedicated bypass-focused tool.
Full StealthGPT review → · Full Grammarly AI Humanizer review →