Updated August 2026 · Grammarly's own pages read first-party
Grammarly AI humanizer: what the Grammarly humanizer does, what it will not do, and the alternative
It is real, it is free with caps, and it is good at making stiff prose readable. One sentence on Grammarly's own page decides whether it is the right tool for you.
2 free runs a day, up to 200 words each. We save your run so you can get back to it, and a delete button appears with the result. See privacy.
This is our own AI-pattern score, measured here on sentence rhythm, template phrases, vocabulary variety and passive voice. It is not a GPTZero, Turnitin, Originality.ai, Copyleaks or ZeroGPT result, and it does not predict one. Worth knowing: we also ask the rewrite to vary sentence length, drop template phrases and prefer the active voice, so some of the drop is built in. Read the two panels below, not just the number.
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Plans planned from $9/month billed yearly · Your runs saved to your history, delete any time
The short answer
Grammarly's AI humanizer is a genuine product at grammarly.com/ai-humanizer, free to use with an unpublished cap, with four preset voices, a custom voice built from a 200-word writing sample, and support for six languages. It rewrites AI-flavored prose into something that reads naturally, and it does that well. What it does not do is stated by Grammarly itself on the same page: "This tool is not intended to bypass AI detectors." If your document is going to be scored by a checker, that sentence, and the fact that Grammarly also sells the detector, is the whole decision.
Last updated August 20, 2026. Every quotation below was read on the vendor's own page on the date shown beside it.
The product, not the marketing
What the Grammarly humanizer actually is
Six things worth knowing before you decide, each read on Grammarly's own pages on August 20, 2026.
Does Grammarly have a humanizer?
Yes, two ways in. There is a standalone page at grammarly.com/ai-humanizer whose H1 reads "Free AI Humanizer: Humanize AI Text", and there is a Humanizer agent inside Grammarly itself. The standalone page invites you to paste text from "ChatGPT, Claude, Google Gemini, and more".
Is the Grammarly humanizer free?
Free to try, capped in practice. Grammarly says the Humanizer agent is available to "Grammarly Pro, Grammarly Plus, and Grammarly Free subscribers", then adds "Upgrade to Grammarly Pro to unlock the full Humanizer experience". Grammarly does not publish the free allowance as a number.
Where is the humanizer in Grammarly?
In the agents tab of the right sidebar when you are in Grammarly docs, and in Superhuman Go. Enterprise, Business and Education accounts get it in docs only. If you cannot find it in the browser extension on a third-party site, that is why.
What are the Grammarly humanizer voices?
Four presets, plus a custom voice. Grammarly's guide says building your own needs "a writing sample of 200 words or more", which is the more useful half of the feature: it matches your existing prose rather than a generic register.
What languages does it support?
Six. Grammarly's page lists English, Spanish, French, German, Portuguese and Italian. That is a wider spread than most standalone humanizers offer, and it is a real advantage if you write in more than one of them.
Does Grammarly say it beats AI detectors?
It says the opposite, in one sentence on its own page: "This tool is not intended to bypass AI detectors." It adds that "the use of AI humanizers can be frowned upon in certain contexts". No competitor page we have read quotes either line.
Most write-ups of this tool get the access model wrong, so it is worth being precise. There are two entry points and they behave differently. The standalone page is a text box on the open web: paste, click, read the result. The Humanizer agent is a feature inside the product, and Grammarly's support guide places it "in Superhuman Go and docs", with Enterprise, Business and Education accounts getting it in docs only. That is why people report the humanizer working on one machine and missing on another. It is not a bug, it is the surface.
The custom voice is the part worth actually using. Feeding it 200 words of writing you produced before you ever touched an AI tool gives the rewrite a target that is specific to you, rather than a generic register called something like Everyday. Uniformity is the property detectors measure most reliably, and matching your own uneven rhythm beats matching an average one. That mechanism is set out in full in how AI detectors work.
The line nobody quotes
Grammarly rules out the thing most people came for
And it sells the checker on the other side of the same question.
Search volume for this tool is enormous, and a large share of it comes from people whose real question is whether the output will clear a detector. Grammarly answers that on the page, in one line: "This tool is not intended to bypass AI detectors." It follows with a caution that "the use of AI humanizers can be frowned upon in certain contexts". Those two sentences are the most useful thing on the page and almost no review of the product mentions them.
The second fact sharpens the first. Grammarly also sells an AI detector, free on the web, and it ships Authorship, which replays how a document was typed. So the same company sells you the rewrite, sells your reader the checker, and sells a third product that records the writing process. None of that is dishonest. It does mean that a Grammarly humanizer output scored by a Grammarly detector is not an independent test of anything, and it explains why Grammarly is careful not to promise the two products will agree.
How careful should you be with the detector half? Grammarly's own detector page claims 99 percent accuracy and also states that "No AI detector is 100% accurate". PCWorld ran a Gemini-written story through it and reported a score of 37 percent, twice. We keep the full picture of what that detector does, including Authorship, on the best AI humanizer for Grammarly page, and the peer-reviewed evidence on detector error rates on the AI detector false positive rate page.
We are going to be equally plain about our own side of this. We do not publish a guaranteed pass rate, because there is no way to earn one. Turnitin sells to institutions and exposes no public API, and it says openly that it trains against rewriting tools and will not name them, precisely so no vendor can know whether it is on the list. Any number you see advertising a Turnitin bypass percentage was produced by the company selling the tool, on a test nobody else can repeat.
Five humanizers, honestly compared
Grammarly humanizer against the alternatives
Prices and quotations were read on each vendor's own page on the date in the first column. Where a vendor does not publish a number, this table says so rather than guessing.
| Tool | Price and limits | What it says about detectors | Where it runs | Worth knowing |
|---|---|---|---|---|
| Grammarly HumanizerChecked Aug 20, 2026 | Free tier with caps. Grammarly says the Humanizer agent is available to "Grammarly Pro, Grammarly Plus, and Grammarly Free subscribers", and invites you to "Upgrade to Grammarly Pro to unlock the full Humanizer experience". | States on its own page: "This tool is not intended to bypass AI detectors." | The standalone page at grammarly.com/ai-humanizer, plus the Humanizer agent inside Grammarly docs and Superhuman Go. Enterprise, Business and Education accounts get it in docs only. | Four preset voices plus a custom voice built from "a writing sample of 200 words or more". English, Spanish, French, German, Portuguese and Italian. |
| QuillBot AI HumanizerChecked Aug 20, 2026 | Free tier "humanize texts of 125 words or fewer". Premium removes it: "No word or usage limit". | Makes no bypass claim. It returns a "Human score" and its own FAQ asks "Should I be worried if my text isn't 100% Human?" rather than promising a number. | quillbot.com/ai-humanizer, plus ChatGPT and Gemini integrations on Premium. | Advanced humanizing and tone insights are Premium only. QuillBot sells an AI detector as well. |
| OpenAI AI HumanizerChecked Aug 19, 2026 | Bundled with a ChatGPT account. | Makes no detector claim at all. Three modes: "Shorten text", "Improve clarity", "Make it original". | chatgpt.com/writing/ai-humanizer. | Carries the notice "Chats may be reviewed and used to improve our AI models", which rules it out for anything confidential. |
| Undetectable.aiChecked Aug 19, 2026 | $5.00 a month billed yearly ($60/yr) for 10,000 words, $9.50 a month yearly for 20,000. | Sells directly on clearing detectors and runs its own multi-detector check. | Web app, browser extension, and a REST API on every paid tier. | The cheapest annual entry price in this comparison, and the only one here with API access on the entry plan. That genuinely beats us. |
| Undetected.ai (us)Checked Aug 19, 2026 | Free account: 3 runs/day, 9,000 words/mo. Paid plans planned at $9 a month yearly for 15,000 words, $19 for 80,000, $39 for 250,000. | One rewrite of your own text, with our AI-pattern score measured before and after and the reasons behind it. We make no promise about any outside detector, because nobody can. | Web app. No public REST API on the self-serve plans. | Runs are saved to your account history so you can come back to them, and you can delete any of them. See the privacy page for what Google Gemini does with the text in transit. |
Read that table by column rather than by row. The price column separates free-with-caps from paid, and the caps matter more than the headline: QuillBot's 125 words per pass on the free tier turns a 2,000-word piece into sixteen separate rewrites, and a second limit of six passes a day caps it at 750 words in twenty-four hours, as we work through on the QuillBot AI humanizer page. The seams between passes are exactly where tone drifts back toward uniform. Grammarly does not publish its free allowance at all, which is its own kind of answer.
The detector column is the one that decides purchases. Two of the five explicitly decline to make a claim, one makes none, and two sell on it. If you are choosing between free tools, that column tells you the free ones are solving a readability problem, not a scoring one, and they say so themselves.
The last column carries the thing each vendor would rather you skimmed. For OpenAI it is the data notice. For Undetectable.ai it is genuinely in their favor: they are cheaper than us annually and put a REST API on every paid tier, which we do not offer on any plan, and if programmatic access on a small budget is your requirement they are the honest recommendation. Their full ladder is on Undetectable.ai pricing. The rest of the paid field is compared on the best AI humanizer page.
How to use it properly
Four steps, in the order that actually works
Step 1
Decide which problem you have
Flat prose and a detector score are different complaints with different fixes. If the draft simply reads like a machine wrote it, Grammarly's humanizer is a reasonable free first pass. If a checker has already flagged it, keep reading.
Step 2
Use the voice, not just the button
The preset voices change register more than the default rewrite does, and a custom voice built from 200 words of your own writing changes it further. Most people click once, get a mild polish, and conclude the tool does nothing.
Step 3
Read the output against your own writing
Open something you wrote before you ever used AI and compare the rhythm. Humanizers fix uniformity; they do not fix a paragraph that says nothing. Cut the hedges and the throat-clearing sentences yourself.
Step 4
Check where the document is actually going
A blog post nobody scores and a paper going into Turnitin are not the same job. If a detector sits at the end of the pipeline, size your tool to that, and understand what it can and cannot promise.
Step one is where most of the disappointment comes from. Someone pastes a ChatGPT paragraph in, gets back a slightly warmer version of the same paragraph, runs it through a checker, sees a high score and concludes the humanizer is fake. It is not fake. It did the job it advertises, which is readability, and it declined the job it does not advertise, which is scoring. Matching the tool to the complaint saves everyone the argument. The model-specific version of that argument is on the ChatGPT humanizer page, and the Claude version on the Claude AI detector page.
Who should use which
Six situations, and the right tool for each
If the first one describes you, stop reading and go use the tool you already pay for.
You already pay for Grammarly
Then use it. The Humanizer is included, it runs where you already write, and for tightening AI-flavored prose in an email or a report it is genuinely good. Paying twice for a mild polish makes no sense.
You write in more than one language
Six languages is a real advantage. Most standalone humanizers in this market are English-only or have an English-only interface with a thin translation layer behind it.
Your document gets scored by a detector
This is where the free tools stop, by their own account. Grammarly states plainly that its humanizer is not intended to bypass AI detectors, and QuillBot makes no bypass claim at all, returning a Human score instead.
The text is confidential
OpenAI's humanizer carries the notice that chats may be reviewed and used to improve its models. If the draft is a client deliverable, an unfiled brief or unreleased research, that notice is the whole decision.
You are pasting past 125 words a lot
QuillBot's free tier caps at 125 words per pass and six passes a day, and stitching a 2,000-word piece together from sixteen passes is where tone drifts. Word caps decide more purchases in this category than accuracy claims do.
You want a number you can act on
Nobody sells one honestly. Turnitin has no public API, so every guaranteed pass rate in this market is an estimate wearing a lab coat. What you can get is a own AI-pattern score, which names what it counted so you can check the reasoning yourself.
Students sit in the hardest position on this list, because the checker their work meets is one they cannot run and whose output they never see. Turnitin shows the AI writing indicator to instructors and administrators, not to students, and suppresses any reading between 1 and 19 percent behind an asterisk. That is a governance problem before it is a writing problem, and it has its own page in the AI humanizer for students. Teams publishing at volume have the opposite problem, consistency across several writers, covered on the AI humanizer for content teams page.
Before you switch tools
Three things we will not tell you
That Grammarly's humanizer is bad. It is not. It is a competent rewriter with six languages, a custom voice trained on your own prose, and a free tier, sitting inside a product millions of people already pay for. If readability is the complaint, it is the cheapest correct answer on this page and you should use it.
That any tool guarantees a detector score. Not us, not Grammarly, not the vendors publishing bypass percentages. GPTZero states that its classifier "is not trained to identify AI-generated text after it has been heavily modified after generation", and that sentence is the entire honest case for this category: heavy editing changes what a classifier sees, and no one can convert that into a promise about your specific document.
That a rewrite fixes a weak draft. A humanizer changes rhythm and register. It does not add evidence, repair a thin argument, or check facts. If the draft contains an invented citation, the rewritten version contains the same invented citation in better prose, which is worse, because it now reads convincingly. That failure mode is covered in whether humanized text can still be detected.
What it costs to move
Sizing a paid plan against what you publish
Our plans are $9 a month for 15,000 words, $19 for 80,000 and $39 for 250,000, all billed annually, or $12, $24 and $48 month to month, and they are planned rather than on sale. Our free account is small on purpose (3 runs a day, 9,000 words a month), which is the honest reason to stay on Grammarly's free humanizer if a free humanizer solves your problem.
Size the tier from output rather than ambition. A 1,200-word article consumes roughly 1,200 words of allowance, so 15,000 words is about a dozen pieces a month. If you draft long and cut hard, count the draft. Undetectable.ai starts lower at $5.00 a month billed annually for 10,000 words, and puts an API on every tier, so on price alone they win; where we differ is our own AI-pattern score on screen, with the reasons behind both numbers.
Frequently asked
Grammarly humanizer questions, answered
Does Grammarly humanizer bypass Turnitin?
Grammarly does not claim it does, and says the reverse: "This tool is not intended to bypass AI detectors." Nobody outside Turnitin can verify a pass rate anyway, because Turnitin sells only to institutions and publishes no public API. Treat every specific Turnitin bypass percentage you see in this market as unverifiable.
Can Grammarly humanizer be detected?
Rewritten text is still scored like any other text, so yes, it can still be flagged. GPTZero states that its classifier "is not trained to identify AI-generated text after it has been heavily modified after generation", which is the honest mechanism behind every tool in this category. Heavier editing moves scores; a light polish usually does not.
Is Grammarly humanizer good?
For readability, yes. It shortens, unstiffens and re-registers prose competently, and the custom voice trained on 200 words of your own writing is better than most presets in this market. For clearing a detector it is explicitly not built for that job, and Grammarly says so on the page.
How much does the Grammarly humanizer cost?
There is a free tier and a paid unlock, and Grammarly does not publish the free allowance as a number. We do not quote a Grammarly Pro dollar figure here because its pricing page varies by region, and a stale price is worse than no price. Check grammarly.com/plans from your own connection.
Why is the Grammarly humanizer not working?
Usually one of three things: you are on a surface that does not carry it (the agent lives in Grammarly docs and Superhuman Go, not everywhere the extension runs), your account type is limited to docs only, or you have used up the free allowance. Enterprise, Business and Education accounts get it in docs only.
Is there a Grammarly humanizer alternative?
Several, and they split by what you need. QuillBot is the closest free equivalent with a 125-word cap. OpenAI ships one inside ChatGPT with a data-use notice attached. Undetectable.ai is the cheapest paid option at $5.00 a month billed yearly. We charge $9 and aim the rewrite at the detectors your document will actually meet.
Does Grammarly humanizer show up as AI?
It can, and the awkward part is that Grammarly sells the detector too. Its own detector page carries the line "No AI detector is 100% accurate" alongside a 99 percent accuracy claim, and PCWorld reported that Grammarly scored a Gemini-written story at 37 percent twice. A company paid on both sides of a question is worth reading carefully.
Grammarly humanizer vs QuillBot: which is better?
QuillBot gives you more control and a visible human score; Grammarly gives you six languages and a custom voice trained on your own writing. QuillBot's free cap of 125 words per pass is the practical difference for long documents. Both sell an AI detector as well as a humanizer.
Does Grammarly have an API for the humanizer?
Not a public one for humanizing text. If programmatic access is your requirement, Undetectable.ai publishes a REST API on every paid tier and WriteHuman prices one by word. Undetected.ai has no API on any plan either, and we would rather say that than let you find out after paying.
Is the Grammarly humanizer safe to use on academic work?
That depends on your institution, not on the tool. Grammarly notes that "the use of AI humanizers can be frowned upon in certain contexts". Check the policy that governs your submission before you use any rewriter, including ours, and keep a record of how the document was written.
Keep reading
The questions behind this one
QuillBot humanizer vs Grammarly humanizer
Two free rewriters from two companies that also sell detectors. What each one caps, and which to pay for.
Best AI humanizer for Grammarly
The other half of Grammarly: its free detector, its 99 percent claim, and what Authorship records.
Does Grammarly detect AI?
What the free checker returns, how it is worded, and where it has been reported to be wrong.
How do AI detectors work?
The two signals every classifier reads, and why a 90 percent score does not mean what people think.
ChatGPT humanizer
Including the humanizer OpenAI now ships inside ChatGPT, and the notice attached to it.
Best AI humanizer
The paid field compared on price, word allowance, data handling and what each vendor will actually promise.
When a free polish is not enough
Paste a paragraph and watch which parts change. If Grammarly already solved your problem, keep your money.
Plans planned from $9/month billed yearly · Your runs saved to your history, delete any time