Introduction
Undetectable AI is one of the largest AI humanizers on the market. The company promotes itself as an AI humanizer that bypasses AI detectors, and its founder (CEO), Christian Perry, publicly claimed that the platform had surpassed 20 million users just two months ago: LinkedIn Post.
However, as of November 5, 2025, the homepage now lists 19,234,741 users, more than one million fewer than earlier claims. This drop raises serious questions. If this number represents their key metric and proudest accomplishment, what explains the decline? Was the original claim inflated, or is the site’s counter unreliable? The inconsistency is notable.
This review takes a closer look at:
- The AI humanizer
- The AI detector
- Pricing and billing structure
- Trustpilot user feedback
Let’s get into it.
Pricing Breakdown
Undetectable AI offers two main subscription models: monthly and yearly.
Here's the current pricing:
Yearly Plan
- $5.00/month (billed as $60/year)
- 10,000 words/month (scalable up to 380,000)
Monthly Plan
- $19.00/month
- 20,000 words/month (scalable up to 380,000)
Features on all plans:
- Passes AI detectors
- High-quality, legible content
- Watermark and future-proofing
- Unlimited Human Auto Typer
- Unlimited AI Detecting
- Access to Smart Job Applier
- AI Question Solver
- Writing level matching
- API compatible
Note: Their pricing used to start at $10/month, but it now starts at $20/month.
AI Humanizer
We used the Undetectable mode to test their AI humanizer on an essay generated by ChatGPT.
Detection Results:
| AI Detector | Result |
|---|---|
| GPTZero | ❌ 100% AI |
| ZeroGPT | ❌ 100% AI |
| Copyleaks | ❌ 100% AI |
| Quillbot | ❌ 100% AI |
| Turnitin | ❌ 100% AI |
Despite the heavy marketing, Undetectable's AI humanizer failed to bypass every major AI detector. Most notably, ZeroGPT features a button beneath its detection results that reads "Humanize Text" and below that it says "Make Your Text Human with Undetectable AI."
Ironically, the very tool it promotes failed to bypass its own detection when we tested it. This contradiction raises questions about product integrity and credibility.
Text Quality
The rewrites were low quality, with inconsistent phrasing and poor structure. They introduced sentence fragments and new grammatical errors. Rather than sounding “more human,” the text became noticeably less natural.
AI Detector
Undetectable's AI detector, powered by TruthScan (truthscan.com), is operated by the same founder.
When we tested fully human-written text, the detector labeled it as 57% AI. In contrast, ChatGPT-generated text was scored as 99% human.
Even more telling, content "humanized" by Undetectable AI was flagged by its own system as 60% AI.
Overall, Undetectable AI’s detector appears misaligned, not only with established third-party tools but also with its own rewriting engine.
Billing Practices & Free Trial Concerns
Undetectable AI previously offered 250 words for free after signup, but that option has since been removed. Users are now required to start a free trial, a change seemingly aimed at collecting billing information upfront.
Fortunately, I found a way to try the product without being charged. When you attempt to delete your account, a popup chat window appears offering 1,000 extra words if you choose to stay. It also displays this message:
Please don't cancel 🥺 What can we do to make you happy? We will do anything to keep you as a happy customer!
This sort of emotional manipulation feels unprofessional, and many users have flagged it as a dark pattern.
Common Billing Complaints
- Unexpected charges right after initiating a free trial
- Confusing cancellation flows
- Trial use triggering annual billing
Trustpilot Reviews
Undetectable AI currently holds a 2.7 ⭐️ Trustpilot rating. While there are some 5-star reviews, many appear suspicious or potentially botted. In contrast, the 1-star reviews consistently cite the same concerns:
Rachael:
I attempted to input a text that was 100% written by AI and yet Undetectable AI said it’s 99% human (completely wrong). I then tried the Humanizer function, and I was given sentences riddled with non-sense such as: "Every dialogue, with a colleague drives home the point that solidarity's n’t rooted in anger but in empathy—…" I only intended to try the product for 3 days but clicked "continue" and was charged $60 for the full year-long subscription. This is a dark pattern and one that others here have noted as well. Customer Support was extremely unhelpful and after much back and forth offered me a partial refund for $10. PLEASE do not use this product. It is a scam.
Chrissie:
They billed me $72 for the year. I signed up to the free, cancel anytime. This is not true. You can cancel but you will not be refunded nor will you have access to the app for the year either and offer no method to contact. Absolute SCAM!
M H:
Humanaziing is absolutely garbage. Don't bother. The site is also misleading on subscriptions.
Customer:
Scammers, the FREE trial is a joke, 300 words but you only find that out AFTER all details and transactions, then if you cancel they still charge you and your bank may not help!
Loise:
Signed up for a “3 day free trial” and you attempted to charge immediately, although the invoice says what I need to pay now is $0.00.
Feature Overload
Undetectable AI originally focused on humanizing and AI detection. But as of 2025, the site has exploded with dozens of tools:
Creation
- AI Essay Rewriter
- AI Essay Writer 🔥
- Paraphrasing Tool 🔥
- AI SEO Content Writer 🔥
- Stealth Writer
- Style Replicator 🆕
- Paragraph Generator 🆕
- Paragraph Rewriter 🆕
- Email Generator 🆕
- Rewording Tool 🆕
- Title Generator 🆕
- YouTube Transcript Tool 🆕
- Bulk Scan 🆕
- Poem Generator 🆕
Education
- AI Chatbot 🆕
- AI Question Solver 🆕
- AI Plagiarism Checker
- Conclusion Generator 🆕
- Citation Tools (APA, MLA)
- Math Solver 🆕
Careers
- Job Applier 🆕
- Cover Letter Generator 🆕
- Resume Generator 🆕
- Business Name Generator 🆕
Detection & Security
- AI Detector 🔥
- Humanizer 🔥
- Watermark Remover 🔥
- AI Image Detector 🆕
- AI Voice/Video Detector 🆕
- Deepfake & Fake Receipt Detection 🆕
- TruthScan 🔥
Productivity
- Grammar Checker 🆕
- Translator 🆕
- Word Counter
- Story Generator 🆕
- Prompt Generator 🆕
While the variety is impressive, this “everything in one” approach has made the platform feel saturated, leaving its main tools, the AI humanizer and detector, inconsistent and unreliable.
Brand Power & SEO
Despite its humanizer issues, Undetectable AI has been exceptionally strong in its branding and SEO.
- They own a top-tier domain:
undetectable.ai - Their backlink profile includes links from Forbes, BuzzFeed, and other major publishers
- Some competitors, such as StealthGPT, have tried to capitalize on Undetectable AI’s brand by including “Undetectable AI” in their Google search title (meta title). For example, “Undetectable AI: StealthGPT and Free AI Checker.”
That said, their attempt to trademark "Undetectable AI" was rejected by the USPTO:
Undetectable AI & StealthGPT USPTO Filings
Both Undetectable AI and StealthGPT attempted to register the name “Undetectable AI” with the USPTO, but neither application was approved or published.
- Undetectable AI Filing — Undetectable AI’s own application was never approved.
- StealthGPT Filing — StealthGPT later filed a separate application using Undetectable's name, which also did not move forward.
These back-to-back filings highlight ongoing attempts by both companies to claim ownership of the “Undetectable AI” brand within the AI humanizer market.
Final Verdict
Undetectable AI has strong branding, a large presence, and a polished interface. However, its core products, the AI humanizer and AI detector, are unreliable. Combined with questionable billing practices, the result is a product that underperforms where it matters most.
We do not recommend Undetectable AI as an AI humanizer or detector.