writing
Best AI Humanizer
AI humanizers rewrite machine-written text so it reads more naturally. No independent test ranks the commercial tools, so this page lists them on their published prices, their own claims and their user ratings, alongside what peer-reviewed research shows about humanised text and AI detectors.
Quick answer: No AI humanizer can be named the best on independent evidence, because no independent test ranks the commercial tools against each other. The public humanizer leaderboards are run by humanizer companies or name no operator, and their latest editions disagree with each other. For making an AI-assisted draft read more naturally at no cost, Grammarly’s AI Humanizer is free on the web, and Grammarly states that the tool “is not intended to bypass AI detectors”. Among dedicated humanisers, Phrasly has the most user ratings, at 4.7 out of 5 from 3,565 Trustpilot reviews, ahead of Undetectable.ai (3.5 from 989), WriteHuman (4.1 from 309) and StealthGPT (3.9 from 204). The peer-reviewed evidence covers humanised text as a category, not any one tool: in a June 2026 study of 160 academic papers, Pangram was 92.5% accurate on humanised papers, Turnitin 50.0%, Copyleaks 22.5% and GPTZero 2.5% (International Journal for Educational Integrity).
This page covers tools that rewrite AI-generated or AI-assisted text so it reads as if a person wrote it. Tools that restate text to make it clearer or more formal are on best AI paraphrasing tools, and the detectors on the other side are on best AI detectors.
Which one should you pick?
| If you want | Pick | Price | What to know |
|---|---|---|---|
| A free rewrite that makes an AI-assisted draft read more naturally | Grammarly AI Humanizer | Free basic version; full version in Grammarly Pro | Grammarly states it is not intended to bypass AI detectors |
| Humanising inside a writing suite | QuillBot AI Humanizer | Limited free use; QuillBot Premium $19.95 a month or $99.95 a year | Also a Premium mode of the QuillBot Paraphraser |
| The dedicated humaniser with the most user ratings | Phrasly | $2 for three days; $10.99 a month billed annually | 4.7 from 3,565 Trustpilot reviews |
| A dedicated humaniser with a free tier | WriteHuman | Free for 3 requests a month; paid from $20 a month | 4.1 from 309 Trustpilot reviews; WriteHuman also operates the HumanizerBench leaderboard |
| A monthly word allowance with a stated refund | Undetectable.ai | From $9.99 a month for 10,000 words | 3.5 from 989 Trustpilot reviews, 41% of them one-star |
| A humaniser bundled with an essay writer and study tools | StealthGPT | $1 for three days, then $299.99 a year | 3.9 from 204 Trustpilot reviews |
| Unlimited words on a yearly plan, in 50-plus languages | HIX Bypass | $15 a month billed yearly; $59.99 month to month | The language count is HIX Bypass’s own figure |
| Certainty that a text will not be flagged | No tool offers it | Not applicable | StealthGPT’s own site says no tool guarantees a 100% bypass, and Turnitin does not name the humanisers it detects |
The current state of AI humanizers
The category is large. Joseph Thibault, the founder of the academic-integrity company Cursive, tracked 43 humanisers that drew a combined 33.9 million website visits in October 2025, and Turnitin’s chief product officer, Annie Chechitelli, said Turnitin had identified 150 such tools, which charge as much as $50 for a subscription (NBC News, 28 January 2026).
No independent test ranks the commercial tools. The peer-reviewed studies test detectors against humanised text without ranking the humanisers. The hands-on comparisons are blog posts, and most “best AI humanizer” lists are published by companies that sell a humaniser.
The leaderboards are run by vendors or by nobody named. HumanizerBench states that it “is operated by WriteHuman”. AI Humanizer Benchmark names no operator. Their October 2026 editions place the same tools in different orders, as the leaderboard table below shows.
Detectors differ widely on humanised text. In the June 2026 International Journal for Educational Integrity study, accuracy on humanised academic papers ranged from 92.5% for Pangram to 2.5% for GPTZero (Van Vlasselaer, Van Droogenbroeck and Spruyt).
Turnitin now reports humanised text inside its main AI score. Turnitin added detection of AI bypasser tools on 27 August 2025, and on 4 August 2026 it merged AI-generated, AI-paraphrased and bypassed text into a single percentage (Turnitin release notes).
Writing-tool companies offer humanisers as readability features. Grammarly describes its humaniser as a tool that “enhances clarity and coherence”, and QuillBot sells a standalone AI Humanizer as well as a Humanize mode in its Paraphraser.
What an AI humanizer does
An AI humaniser rewrites text to change the statistical properties that AI detectors measure. Detectors look at how predictable each word is and how much sentence length and rhythm vary, and a humaniser swaps vocabulary, varies sentence length and restructures clauses to move the text away from the pattern a detector flags. Our guide to how AI detectors work covers the signals in detail.
A humaniser changes how text reads. It does not add original thinking, check facts or change who wrote the text. Researchers at Pangram Labs studied 19 humaniser and paraphrasing tools and assessed how faithfully each one preserved the meaning of the original text (Masrour, Emi and Spero, arXiv).
What independent research shows
None of these studies ranks commercial humanisers against each other. Each one measures detectors against humanised text.
| Study | What was tested | Finding on humanised text |
|---|---|---|
| Van Vlasselaer, Van Droogenbroeck and Spruyt, International Journal for Educational Integrity, June 2026 | GPTZero, Copyleaks, Turnitin and Pangram on 160 academic papers: human, AI-written, hybrid and humanised | Average AI score on humanised papers (actual 44.8%): Pangram 43.6%, Turnitin 35.3%, Copyleaks 23.4%, GPTZero 21.2% (supplementary Table 7) |
| Jabarian and Imas, NBER working paper 34223, September 2025 | Pangram, Originality.ai, GPTZero and an open-source RoBERTa detector across genres, lengths and models | Pangram’s error rates stayed near zero and “robust across” humaniser tools, according to the paper’s abstract |
| Cheng, Sadasivan, Saberi, Saha and Feizi, NeurIPS 2025 | A research attack that paraphrases AI text while steering against a detector’s score | An average 87.88% reduction in detectors’ true-positive rate at a 1% false-positive rate. This is a research method, not a commercial product |
| Masrour, Emi and Spero, arXiv, January 2025 | 19 humaniser and paraphrasing tools. The authors work for Pangram Labs, which sells a detector | The paper reports that many existing AI detectors fail to detect humanised text, and presents Pangram’s own detector as robust to it |
Turnitin’s results in the 2026 study predate its later model updates, and Turnitin has not published which humanisers its bypasser detection covers. Our Turnitin AI detection guide sets out the dates.
Why these tools are listed, not ranked
A ranking needs more than one independent assessment of each product. For AI humanisers the public assessments are vendor-run or anonymous, and they contradict each other. The table shows where three sources placed the same two tools.
| Source | Who runs it | Undetectable.ai | WriteHuman |
|---|---|---|---|
| HumanizerBench, October 2026 | WriteHuman, by the site’s own disclosure | 3rd of 14, score 71.18 | 1st of 14, score 74.89 |
| AI Humanizer Benchmark, October 2026 | No operator named | 11th of 11, score 33.60, with a 1.8% bypass rate | 7th of 11, score 75.06, with a 97.6% bypass rate |
| Best AI Humanizer (August 2026), Substack, 27 July 2026 | Published under the name Humanize AI; no author named | 79.7% | 74.1% |
HumanizerBench scores against six detectors, including Pangram from its October 2026 edition, and does not test Turnitin directly. AI Humanizer Benchmark scores 33 samples per tool against seven detectors and includes neither Pangram nor Turnitin.
For that reason the tools below are listed on what each vendor publishes and on their user ratings. A vendor’s bypass figure is its own claim, measured on its own samples.
AI humanizers compared
| Tool | What it is | Free | Paid | Trustpilot |
|---|---|---|---|---|
| Grammarly AI Humanizer | Humaniser from a writing assistant | Basic version, free | Full version in Grammarly Pro | Not rated as a separate product |
| QuillBot AI Humanizer | Humaniser from a writing toolkit, also a mode in the QuillBot Paraphraser | Limited free use; the Paraphraser mode is Premium only | Premium $19.95 a month, $99.95 a year | Not rated as a separate product |
| Phrasly | Dedicated humaniser with plagiarism checker and content generator | No; $2 for three days | Unlimited $10.99 a month, billed annually | 4.7 from 3,565 |
| Undetectable.ai | Dedicated humaniser with detector and API | 250-word trial | $9.99 to $42.50 a month by word allowance | 3.5 from 989 |
| WriteHuman | Dedicated humaniser with detector | 3 requests a month, 250 words each | $20, $29 or $59 a month | 4.1 from 309 |
| StealthGPT | Humaniser bundled with an essay writer and study tools | No; $1 for three days | Pro $299.99 a year, Max $499.99 a year | 3.9 from 204 |
| HIX Bypass | Dedicated humaniser with detector and API | None listed | $14.99, $29.99 or $59.99 a month | HIX.AI suite: 3.0 from 192 |
Grammarly AI Humanizer
Grammarly’s AI Humanizer turns “AI-generated text from ChatGPT, Claude, Google Gemini, and more into writing that sounds natural and engaging”, in Grammarly’s words. A basic version is free on Grammarly’s website. A Grammarly account opens the Humanizer agent, and Grammarly Pro adds four voice options, custom voice profiles and support for six languages. Grammarly states: “This tool is not intended to bypass AI detectors. Instead, it enhances clarity and coherence, helping AI-assisted writing feel more polished and readable.”
Good for: a free rewrite of an AI-assisted draft, from a company that states the tool’s purpose as readability.
QuillBot AI Humanizer
QuillBot sells a standalone AI Humanizer with limited free use, and Premium removes the limits. It also includes Humanize among the modes of its Paraphraser, alongside Formal, Simple, Creative, Academic, Expand and Shorten. That mode is Premium only (QuillBot Help Center). QuillBot Premium costs $19.95 a month, $39.95 a quarter or $99.95 a year (QuillBot Help Center). The Paraphraser itself is covered on best AI paraphrasing tools.
Good for: people who already use QuillBot for other writing tasks.
Phrasly
Phrasly is a dedicated humaniser with a plagiarism checker and a content generator. Its pricing page lists three-day access for $2 with 1,000 humanisation words, and an Unlimited plan at $10.99 a month billed annually with unlimited humanisation, 5,000 words per pass and plagiarism checks on 100,000 words a month. Phrasly holds 4.7 out of 5 from 3,565 reviews on Trustpilot, with 92% five-star and 7% one-star. That is the largest body of user ratings of any dedicated humaniser on this page.
Good for: unlimited humanising on an annual plan.
Undetectable.ai
Undetectable.ai sells a humaniser with a built-in AI detector, writing-level matching and API access. Its pricing page lists 10,000 words a month for $9.99 ($5.00 a month billed annually), 20,000 words for $19.00, 35,000 words for $31.00 and 50,000 words for $42.50, with a 250-word free trial. The page advertises a “money-back guarantee” if humanised output is flagged as not human; that is Undetectable.ai’s own term. Undetectable.ai holds 3.5 out of 5 from 989 reviews on Trustpilot, with 50% five-star and 41% one-star. The one-star reviews mostly concern unexpected charges and difficulty cancelling.
Good for: paying by monthly word allowance.
WriteHuman
WriteHuman is a dedicated humaniser with a built-in detector. Its pricing page lists a free tier of 3 requests a month at up to 250 words each. Basic costs $20 a month ($12 billed annually) for 80 requests of up to 600 words, Pro $29 ($19 billed annually) for 200 requests of up to 1,200 words, and Ultra $59 ($39 billed annually) for unlimited requests of up to 3,000 words. Paid plans return two to five variations of each rewrite. WriteHuman holds 4.1 out of 5 from 309 reviews on Trustpilot, with 71% five-star and 21% one-star. WriteHuman operates HumanizerBench, the leaderboard that ranked WriteHuman first in November 2026.
Good for: trying a dedicated humaniser without paying.
StealthGPT
StealthGPT bundles a humaniser with an AI detector, an essay writer, an SEO writer, a PDF chat tool and a Chrome extension. StealthGPT says its humaniser will “bypass AI detection and preserve the quality, context, and natural rhythm of your content”, and reports a “98% human average” on Turnitin across 30 of its own samples. Its site also states: “No tool guarantees 100% bypass.” Its pricing page lists Pro at $299.99 a year for 50,000 words a month and Max at $499.99 a year for 200,000 words a month; each can be started at $1 for three days, after which it renews at the yearly price. StealthGPT holds 3.9 out of 5 from 204 reviews on Trustpilot, with 65% five-star and 19% one-star.
Good for: people who want a humaniser and an essay-drafting tool in one subscription.
HIX Bypass
HIX Bypass is a dedicated humaniser with a detector, three rewrite modes (Fast, Aggressive and Latest) and an API. Its pricing page lists Standard at $14.99 a month ($9.99 billed yearly) for 5,000 words a month, Premium at $29.99 ($14.99 billed yearly) for 50,000 words, and Unlimited at $59.99 ($15 billed yearly) with no word cap. Standard and Premium take up to 3,000 words per input. HIX Bypass says it supports more than 50 languages. HIX.AI, the suite it belongs to, holds 3.0 out of 5 from 192 reviews on Trustpilot, with 44% five-star and 46% one-star.
Good for: humanising in languages other than English, on HIX Bypass’s own description.
What users say
Trustpilot ratings record customer satisfaction, including billing and support. They do not measure whether a text passes a detector.
| Tool | Score | Reviews | Five-star | One-star | Most common complaints |
|---|---|---|---|---|---|
| Phrasly | 4.7 | 3,565 | 92% | 7% | Human writing flagged as AI; occasional awkward output |
| WriteHuman | 4.1 | 309 | 71% | 21% | No refunds; output still flagged by some detectors |
| StealthGPT | 3.9 | 204 | 65% | 19% | Cancellation and billing; grammatical errors in output |
| Undetectable.ai | 3.5 | 989 | 50% | 41% | Unexpected charges; cancelling by email |
| HIX.AI (suite) | 3.0 | 192 | 44% | 46% | Subscriptions and refund disputes |
Trustpilot notes on the Phrasly, StealthGPT and Undetectable.ai profiles that the company has not invited reviews recently, so the reviews may not be representative.
Humanizers and academic integrity
Turnitin treats humanisers as “AI bypasser tools” and reports text it believes was run through one as AI-generated. Turnitin’s chief product officer told NBC News that the tools exist to help students cheat. Students told NBC News they also use humanisers on work they wrote themselves, to avoid being wrongly flagged by a detector. Grammarly’s humaniser page says Grammarly “encourages transparent and responsible AI use, including clearly acknowledging AI assistance in academic or professional work”.
Whether using a humaniser breaks a rule depends on the policy of the institution or employer the work is submitted to. A detector flag is not proof of AI use, and our best AI detectors page covers false positives and what the detectors’ own makers say about their limits.
Recent developments
- October 2026. HumanizerBench added Pangram to the detectors it scores against (HumanizerBench).
- 4 August 2026. Turnitin merged AI-generated, AI-paraphrased and bypassed text into a single AI writing percentage and stopped showing separate highlights for paraphrased text (Turnitin release notes).
- 29 July 2026. Pangram released Pangram 4, aimed at mixed human-AI text and humaniser output (Pangram).
- June 2026. The International Journal for Educational Integrity published the 160-paper study of four detectors, including humanised papers (IJEI).
- 28 January 2026. NBC News reported 33.9 million combined visits to 43 humanisers in October 2025 (NBC News).
- 27 August 2025. Turnitin added detection of AI bypasser tools to its AI writing report (Turnitin release notes).
Frequently asked questions
What is the best AI humanizer?
No AI humanizer can be named the best on independent evidence, because no independent test ranks the commercial tools against each other and the public leaderboards are run by humaniser companies or name no operator. Grammarly’s AI Humanizer is free and is described by Grammarly as a readability tool. Among dedicated humanisers, Phrasly has the most user ratings, at 4.7 out of 5 from 3,565 Trustpilot reviews, followed by Undetectable.ai at 3.5 from 989, WriteHuman at 4.1 from 309 and StealthGPT at 3.9 from 204.
Do AI humanizers work against AI detectors?
It depends on the detector. In a June 2026 study in the International Journal for Educational Integrity, accuracy on humanised academic papers was 92.5% for Pangram, 50.0% for Turnitin, 22.5% for Copyleaks and 2.5% for GPTZero (Van Vlasselaer, Van Droogenbroeck and Spruyt). The study did not rank individual humanisers, and no independent test of named commercial humanisers has been published.
Can Turnitin detect humanized text?
Turnitin says it can. Turnitin added detection of AI bypasser tools on 27 August 2025 and has reported bypassed text inside its single AI writing percentage since 4 August 2026. Turnitin does not name the humanisers it detects. In the June 2026 International Journal for Educational Integrity study, Turnitin’s average AI score on humanised papers was 35.3% against an actual 44.8%; Turnitin has updated its model since.
Is there a free AI humanizer?
Yes. Grammarly’s AI Humanizer has a free basic version on Grammarly’s website. WriteHuman’s free tier allows 3 requests a month of up to 250 words each, and Undetectable.ai offers a 250-word free trial. Phrasly charges $2 for three days of access.
Is Grammarly’s AI Humanizer free?
Yes, the basic version is free on Grammarly’s website. A Grammarly account opens the Humanizer agent, and Grammarly Pro adds four voice options, custom voice profiles and six languages. Grammarly states that the tool is not intended to bypass AI detectors.
How much does Undetectable.ai cost?
Undetectable.ai costs $9.99 a month for 10,000 words, or $5.00 a month billed annually. Its larger plans cost $19.00 a month for 20,000 words, $31.00 for 35,000 words and $42.50 for 50,000 words, and it offers a 250-word free trial.
Which AI humanizer leaderboard is independent?
Neither public leaderboard on this page can be shown to be independent. HumanizerBench states that it is operated by WriteHuman and ranked WriteHuman first in October 2026. AI Humanizer Benchmark names no operator. In October 2026 HumanizerBench placed Undetectable.ai third of 14 tools, and AI Humanizer Benchmark placed Undetectable.ai last of 11.
What is the difference between an AI humanizer and a paraphrasing tool?
Both rewrite text, for different purposes. A paraphrasing tool restates text to make it clearer, plainer or more formal. An AI humaniser rewrites text so it reads as if a person wrote it, and many are marketed on lowering AI-detector scores. Our best AI paraphrasing tools page covers the first group.
Is using an AI humanizer cheating?
It depends on the rules the work is submitted under. Turnitin classes humanisers as AI bypasser tools and reports their output as AI-generated text. Students told NBC News in January 2026 that they also run their own writing through humanisers to avoid false flags from detectors. Grammarly says users should acknowledge AI assistance in academic or professional work.
Do I need an AI humanizer for SEO?
No. Google’s guidance, published in February 2023, says Google rewards quality content however it is produced, and treats automation used to manipulate search rankings as spam (Google Search Central). The guidance sets no penalty for text because an AI model wrote it.
Conclusion: how to choose
No AI humanizer is ranked first here, because no independent test ranks the commercial tools against each other.
- For a free readability rewrite: Grammarly’s AI Humanizer.
- If you already pay for QuillBot Premium: the Humanize mode in the QuillBot Paraphraser.
- For the dedicated humaniser with the most user ratings: Phrasly, at 4.7 from 3,565 Trustpilot reviews.
- For a free tier on a dedicated humaniser: WriteHuman.
- For a monthly word allowance: Undetectable.ai, from $9.99 a month.
A vendor’s bypass rate is its own claim. The independent research measures detectors, and the June 2026 study puts Pangram at 92.5% accuracy on humanised papers. For the detectors themselves, see best AI detectors; for writing with AI from the start, see best AI for writing and best AI for essays.