Undetectable AI

What Undetectable AI is

Undetectable AI is a humanizer first and a detector second, and the order matters. The paid product is a rewriter: you paste AI-generated text, pick a readability level, a purpose and a humanization strength, and it returns prose intended to score as human-written on AI detectors. The free product is an AI text detector, plus an image detector, and the marketing leads with the detector. The two sit on the same page. One of them exists to defeat the thing the other one measures.

Mechanically it runs three humanizer models. Signed out, you get the Basic Public Model, and the vendor's own interface puts a warning above the output saying that AI detectors might still flag your text with it. The Stealth and Undetectable models are gated behind an active plan or trial. Controls are more granular than most rivals bother with: readability levels running from High School up to Doctorate, with a Journalist setting alongside; purpose presets including Essay, Cover Letter, Business Material and Legal Material; and three strengths, More Readable, Balanced and More Human, the last of which the tooltip describes as being for overly aggressive detectors. Billing is metered by word, not by seat or by run. Around that core sits an unusually wide accessory suite: an AI essay writer, an SEO content writer, a stealth writer, a paraphrasing tool, a plagiarism checker, a text watermark remover, a Human Typer, an AI job applier, a Chrome extension the homepage says works from Google Docs to Gmail to any webpage, and a developer page at undetectable.ai/develop listing six APIs (Humanizer, Check for AI, Image Detector, Writing Style Replicator, Audio Detector and Video Detector) plus a Zapier integration and an embeddable widget.

One detail on that developer page matters more than the rest. The image, audio and video detector APIs are each labelled "Powered by TruthScan", a third party. So when this page says the company sells both the humanizer and the detector that scores it, the text detector is the vendor's own and the media detectors are white-labelled from someone else. Neither arrangement changes the conflict of interest; it does change who you are actually trusting.

What nobody can verify, us included, is the part you are actually buying. Evasion is a moving target: a humanizer's success rate against Turnitin, GPTZero or Originality.ai is a snapshot that expires the next time those vendors ship a model, and the search results for independent humanizer testing are almost entirely affiliate pages run by competing humanizers. We did not test the humanizer against any detector, and we would not trust a single-date result if we had. Undetectable AI's ethics page is, to its credit, franker about detection than most detector vendors manage: it states that AI text detection in its current state is not enough to objectively rule out the use of AI, and it lists cheating in school and circumventing no-AI policies as unacceptable use. Several of the product's own settings are hard to read as anything else.

Pricing

Undetectable AI publishes every price without a login, which already puts it ahead of several tools in this category. Plans are metered in humanized words per month. The entry plan is $9.99 a month for 10,000 words on monthly billing, or $5.00 a month billed annually, printed as $60.00 a year. Every plan card shows the monthly price struck through beside the annual rate, the annual toggle is labelled "50% off", and the site's main navigation carries a permanent red SALE badge on the Pricing link, so treat the annual figure as the standing price and the monthly figure as the premium for flexibility.

All figures in US dollars, read from undetectable.ai/pricing in September 2026. The help centre's payment surcharge article states that prices are displayed in USD, that currency conversion fees may apply depending on your bank, and that some countries add VAT to digital purchases.

How to read the trial, the annual toggle and the word meter

The trial is 250 words, not three days of a plan. Directly beneath the plan cards the page states that the free trial is limited to 250 words and that additional usage requires paid plan activation. Three days is the clock; 250 words is the budget, roughly half a page. It is offered on annual plans only. The pricing page's structured-data FAQ says no credit card is required to start, while the trial interface's own strings read "No charge today. Cancel anytime before the trial ends", "End your free trial immediately" and a countdown of days left in trial. Those are the strings of a card-on-file trial that converts. Because the trial exists only on annual plans, the charge at conversion is more plausibly the annual total ($60.00, $114.00 or $189.00) than a monthly figure. The page's own template for that line reads "$$planPrice / month after trial ends", which is unfilled, so we could not confirm the basis without completing checkout, and we did not. Read the checkout screen.

The 50K plan has two prices on the same page. The rendered card shows $42.50 struck through above $21.25 a month. The page's plan configuration, the same source that defines the 80K to 380K slider tiers, lists the 50,000-word tier at $42. The card is what a buyer sees; the configuration is what the slider is built from. At $42.50 the unprinted annual total would be $255.00; at $42 it would be $252.00. The page prints neither.

The pricing page's structured data contradicts the page it is on. Its FAQ answer says the yearly plan is $5 a month billed annually at $60 while the monthly plan is $19 a month, and its offer schema publishes a low price of 5.00 and a high price of 19.00. The same page sells plans up to $209 a month, and the actual entry monthly price is $9.99; $19 is the 20K tier. Anyone reading the site through a search engine or an AI assistant gets a different price list from anyone reading the page.

Budget in words, and assume they expire. The Business card sells "permanent words with no monthly expiration" as the thing that distinguishes it, which is the vendor telling you that consumer allowances reset monthly. What the vendor does not say anywhere we could find is whether re-running the same passage a second time deducts the words again. On a tool people re-run repeatedly to chase a score, that is the number that decides your real bill. The one metering fact that is documented sits on the developer page: Check for AI API calls are billed from the same word balance at one tenth the humanize cost, so checking 100 words costs 10 credits.

Two guarantees are stated. Visible on the pricing page: if anything the tool produces is flagged as not human, the company will refund the cost of humanization, which refunds words rather than a subscription. In the pricing page's FAQ: a satisfaction guarantee with a full refund if you contact support within the first 7 days. We have not tested either.

What we verified, and what we did not

Reviews of tools like this often imply a score covers whether the thing works. This one does not, so here is the boundary in plain terms.

Verified: every price and plan limit in the table above, read from the rendered pricing page and its underlying plan configuration in September 2026; the trial cap, the annual-only condition and the trial interface strings; the API list, the TruthScan labels and the API billing basis on the developer page; the free detector's no-account access, its 10,000-word field and its daily-limit interstitials; the ethics page's statements on detection and on unacceptable use; the user-count figures on the homepage and the about page; the Forbes banner; and the USD, conversion-fee and VAT statements in the help centre.

Not verified: whether the humanizer evades any detector, at any setting, on any date; detector accuracy; whether unused words roll over; whether a re-run deducts words again; what is charged when the trial converts; uptime, latency, output quality and support responsiveness. No hands-on testing was performed for this page.

That means the score below is a score for pricing transparency, feature breadth, documentation and trustworthiness of the vendor's own claims. It gives no credit, in either direction, for evasion performance.

The site's claims, side by side

Because the product's central promise cannot be tested from outside, we did the next best thing and read the vendor's pages against each other. These pairs were all live on the same day.

None of this is evidence the product is bad. It is evidence that the marketing runs ahead of what the vendor's own pages support, and that is the surface people buy on.

Where Undetectable AI is the strongest pick

Undetectable AI is at its strongest for a content team that is allowed to use AI, wants to remove the recognisable tells from drafted copy at volume, and wants the cheapest metered way to do it with a real API behind it. Ten thousand words for $9.99 a month, or $5.00 a month on an annual plan, undercuts everything comparable we list, the prices are published in full, and the developer page documents six endpoints plus Zapier with the billing basis spelled out. Nobody else in this cluster gives you all three of those at once.

The second argument is the free detector. It needs no account, it accepts long passages, and as a second opinion alongside a detector with no stake in the answer it costs nothing. Treat its score as one input, never as a verdict, and it earns its place.

Best for

Marketers, agencies and content teams who need to strip the tells out of AI-drafted copy at volume, are working somewhere AI use is permitted, and want the cheapest metered humanizer with a documented API. Also reasonable as a free second-opinion detector, provided you treat its score as one input and never as a verdict. Not for students or anyone submitting graded work: the vendor's own ethics page calls that unacceptable use, and every institution we are aware of treats it as misconduct. Not for institutions or publishers who need a detector they can defend in a disciplinary process: buy that from a vendor that does not also sell the tool designed to beat it.

Key features

• AI humanizer with three models: Basic Public (free, with the vendor's own warning that detectors may still flag it), Stealth and Undetectable (plan or trial only)
• Readability targeting from High School up to Doctorate, plus a Journalist setting
• Purpose presets including Essay, Cover Letter, Business Material and Legal Material
• Three humanization strengths, More Readable, Balanced and More Human, the last described as being for overly aggressive detectors
• Free AI text detector, no account required, accepting up to 10,000 words per check, with a daily limit on free checks
• Free AI image detector, plus audio and video detection through the API, the media detectors labelled "Powered by TruthScan"
• Chrome extension that the homepage says runs from Google Docs to Gmail to any webpage
• Developer page with six APIs (Humanizer, Check for AI, Image Detector, Writing Style Replicator, Audio Detector, Video Detector), a Zapier integration and an embeddable widget; detection billed at one tenth the humanize cost from the same word balance
• Human Typer, which retypes a document into a target editor to produce a keystroke history
• Accessory suite: AI essay writer, SEO content writer, stealth writer, paraphrasing tool, plagiarism checker, text watermark remover and an AI job applier
• 50+ languages supported, with English described by the vendor as the most accurate

Best-fit use cases

• Removing the recognisable tells from AI-drafted marketing copy, blog posts and product descriptions where AI use is permitted but robotic phrasing is not
• Rewriting human-written copy that a client's or editor's detector has false-flagged as AI, which the vendor's ethics page names as a legitimate case
• Running a free second-opinion AI check on inbound freelance or agency copy, as one input alongside a detector with no stake in the result
• Bulk humanization through the API inside an existing content pipeline, billed against a shared word allowance
• Checking whether a supplied image is AI-generated, using the free image detector
• Agency and reseller use under the Business plan's white-labeling and non-expiring credits

Pros

• Cheapest credible entry point in the cluster: $9.99 a month for 10,000 words on monthly billing, or $5.00 a month billed annually at $60.00 a year
• Prices are published in full, without a login, including the volume ladder up to 380,000 words a month
• The AI text detector and image detector are genuinely free and need no account, which is unusual in a category that mostly meters detection
• Humanization controls are more specific than rivals bother with: readability level, document purpose and strength are three separate axes, not one slider
• Documented developer page with six APIs, Zapier and a widget, and the metering basis is stated in plain text: detection costs one tenth of humanization from the same balance
• The ethics page is more honest about detection than most detector vendors' pages: it states that detection cannot objectively rule out AI use and names the misuse cases
• Chrome extension removes the copy-paste loop that makes most tools in this category tedious
• The guarantee is specific and checkable: it refunds the cost of humanization if output is flagged as not human

Cons

• The company sells both the evasion tool and the detector that grades it, so the score telling you the humanizer worked is produced by the humanizer's own vendor
• The free humanizer deliberately runs a weaker model: the interface warns that detectors might still flag text from the Basic Public Model, so free output is not a sample of the paid product
• The free trial is 250 words in total across three days, on annual plans only, and the charge at conversion is not stated in plain text
• Two pages of the same site, fetched the same day, give different user counts: 24M+ on the homepage, +8M in the about page's CEO bio
• The pricing FAQ says no credit card is required to start while the trial screen reads like a card-on-file flow, with a countdown and an end-trial-early button
• "Rated #1 Best AI Detector by Forbes!" runs as a persistent banner; we could only trace it to inclusion in a Forbes roundup of ten detection tools
• The 50K card says $42.50 while the page's own configuration says $42, and the page's structured data advertises a $19 monthly plan as though it were the entry price
• The image, audio and video detector APIs are white-labelled from TruthScan, which the marketing does not mention
• Word allowances expire monthly, by the Business card's own wording, and nothing published says whether a re-run deducts words a second time
• The accessory suite sprawls into Fake ID, Fake Receipt and Fake PDF detectors that have little to do with the core product and are not evidenced anywhere
• Whatever evasion rate the tool achieves today is perishable by design and cannot be relied on next quarter

What to watch out for

Four things, in order of how much they should affect your decision.

The conflict of interest is structural, not incidental. Undetectable AI sells the humanizer and the detector that scores the humanizer's output. When the tool tells you your rewritten text reads as human, that number comes from the company that was paid to make it read that way, and for images, audio and video the score comes from a third party, TruthScan, wearing the vendor's brand. This is not a hypothetical concern about incentives; it is the whole product loop. Use a detector from someone with no stake in the answer, Pangram, Originality.ai, Copyleaks or GPTZero, before you conclude anything worked. The vendor effectively concedes the point on its own ethics page: a detection score is a probability, and one score alone proves nothing.

The free version is not a sample of the paid version. Signed out, you get the Basic Public Model, and the interface warns that detectors might still flag it. Anyone judging the product from the free tool is judging a model the vendor has told you is worse. That is an unusually transparent way to run a funnel, but it means the free tier answers no question you actually have, and the trial that unlocks the better models is 250 words on an annual plan, which is about half a page.

The headline claims do not survive being read side by side. The homepage says 24M+ users; the about page says +8M. The pricing FAQ says no credit card; the trial screen says no charge today and counts down. The Forbes banner says rated number one; what we could find is a ten-tool roundup. The 50K card says $42.50; the page's configuration says $42. The structured data says the monthly plan is $19; the page sells from $9.99 to $209. None of this makes the product bad. It does mean the marketing runs well ahead of what the vendor's own pages support.

The academic framing is genuinely uncomfortable. The ethics page lists cheating in school and circumventing no-AI policies as unacceptable uses, and we take that at face value. But the humanizer's readability presets start at High School, Essay is a purpose preset, there is a dedicated AI essay writer, there is a Human Typer that manufactures a keystroke history for a document you did not type, and the about page says the company exists to help people use AI with confidence in their daily work and academic life. A product configured that specifically for coursework is not neutral about who is buying it. If you are a student, understand that using this on submitted work is academic misconduct at essentially every institution, that the vendor's own policy says so, and that Human Typer in particular is hard to characterise as anything but fabricating evidence of authorship.

One practical footnote: budget in words, not months. Everything is metered per word, the Business card's own copy implies consumer allowances expire monthly, and nothing published tells you whether re-running a stubborn paragraph deducts the words again. The one metering fact that is documented is that API detection costs a tenth of humanization from the same balance.

Is Undetectable AI worth it?

Yes, for the buyer it is actually built for: a marketer or content team with permission to use AI, a real volume of copy to clean up, and no need to defend a detection score to anyone. On that job it is the cheapest published option we list, the controls are more specific than the competition's, and the API and Chrome extension mean it can sit inside a pipeline rather than a browser tab.

It scores 3.6 rather than higher for reasons that have nothing to do with output quality, which we did not measure. Publishing every price without a login, documenting the API billing basis, and writing an ethics page that admits detection is probabilistic are all things that competitors in this category fail to do, and they earn real credit here. What holds the score down is the company's own material: it sells the tool and the judge of the tool, its media detectors are someone else's under its brand, and its pages disagree with each other on user counts, on whether the trial takes a card, and on what the 50K plan costs. A vendor that is this candid on its ethics page and this loose on its homepage is asking you to decide which one to believe.

Worth saying plainly: whether the humanizer beats Turnitin, GPTZero or Pangram this month is the question most readers arrived with, and this page does not answer it. Nobody can, durably. If the guarantee holds, the worst case on a monthly plan is $9.99 and a refund of the words that failed.

How we arrived at 3.6

The score is weighted across eight categories, each marked out of 5. The weights are published so the number can be reproduced, and market trust and value carry the most weight because they are the two things a buyer of this product can actually evaluate from outside.

The 5 point score is a direct weighted mean of the table, and it reflects a cheap, well-documented humanizer sold by a vendor whose own pages are the strongest argument for buying your detection somewhere else.

FAQ

Pricing, plan limits, trial terms, API list and feature claims verified 3 September 2026 from undetectable.ai/pricing (rendered page and underlying plan configuration), undetectable.ai/develop, undetectable.ai/ai-detector, undetectable.ai/ethics, undetectable.ai/about-us, the homepage and the help centre's payment surcharge article. No hands-on testing was performed and no evasion claim is made. ToolChase received no payment for this review. Scores, rankings and list positions are never sold. See our methodology for how we score tools.