Updated July 2026 · prices re-checked July 26
Copyleaks humanizer: the best AI humanizer for Copyleaks AI detection
Copyleaks is the detector you never chose. It runs inside Canvas, Moodle and Blackboard, inside a Google Docs add-on and inside a browser extension, so most people meet it as a report someone else is already reading.
So here is what each humanizer costs, what a Copyleaks scan actually measures, and where each tool loses. Ours included.
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.
Before ·
After ·
Meaning kept · Your own text rewritten · Saved to your history, delete any time
The short answer
Copyleaks does not sell a humanizer, so every tool ranking for the phrase is a third-party rewriter. What separates them for this detector is scope. A Copyleaks scan returns an AI percentage and a similarity score from the same submission, and it publishes the lowest false-positive claim in the category, .03 percent, which is precisely why the person reading your report treats it as settled. That figure deserves more scrutiny than it usually gets, and we unpacked it in full in our breakdown of the Copyleaks false positive rate. Undetected.ai rewrites in one pass and shows our own AI-pattern score before and after, from $9 a month for 15,000 words. Undetectable.ai is the cheapest serious option at about $5 a month billed yearly, with 10,000 words. WriteHuman meters by request rather than by word, which is better value on long documents. Walter Writes gives the most words per dollar but caps each request at 750 words on its entry plan. QuillBot is a strong writing suite that makes no detector promise, and should not be bought as if it did.
Last updated August 4, 2026, when Copyleaks' own accuracy table was re-read and the .03 percent English figure confirmed unchanged. Its pricing and product line were read July 26. Undetectable.ai was re-read July 31, BypassGPT August 4, WriteHuman and Walter Writes July 31, QuillBot August 1. All figures in USD, and promotional rates move constantly, so confirm before you buy. We are not affiliated with Copyleaks.
Before you compare tools
What a Copyleaks scan actually measures, and what it costs the person running it
Copyleaks is priced and deployed differently from the detectors you can run on yourself, and those differences change both what a rewrite has to do and how the person scanning you behaves. Every figure below was read off Copyleaks' own site on July 26, 2026.
| What it is | The published detail | Why it matters to you |
|---|---|---|
| Where it runs | LMS integrations, an API, a Chrome browser extension and a Google Docs add-on that scans from inside the document | You often never see the report. It is generated where the work is submitted, and the first you hear of it is the conversation afterwards |
| The false-positive claim | ".03% false positive rate," advertised as industry-low, alongside "over 99% accuracy" | Three in ten thousand. That single number is the reason a Copyleaks flag is the hardest to argue with, and it comes from the vendor's own English test set |
| How scans are billed | Unified credits. One credit scans 250 words or one image. Personal carries 1,200 credits a year, Pro carries 12,000 | The same credit pool covers text, images, video and code, so the buyer is purchasing an integrity suite rather than an AI checker |
| Cost per 1,000 words scanned | About $0.56 on Personal ($167.88 a year for 300,000 words) and about $0.30 on Pro ($899.88 for 3,000,000 words) | Roughly 8x what Originality.ai Pro charges per word scanned, and about 4.6x on the Pro tier. Nobody buys Copyleaks for cheap word scanning |
| Two numbers, one submission | The AI percentage and the similarity score are calculated independently and neither affects the other | A rewrite that lowers one can raise the other. Paraphrasing around a source is the classic way to trade an AI flag for a plagiarism flag |
| Text length limits | Web platform: 255 characters minimum, up to 2,000 pages. Browser extension: 350 characters minimum, 25,000 maximum | Short passages sit closest to the floor the model needs, and readings taken there are the least stable the tool produces |
| Adjustable sensitivity | Enterprise deployments can "fine-tune detection thresholds to reduce false positives or uncover more nuanced AI rewrites" | Your score is partly a policy setting. The same paragraph can read differently at two institutions running the same product |
| Source code detection | The detector identifies AI-generated source code "even if altered," sold under code governance and compliance | Programming assignments and committed code are in scope, which is not true of most detectors people compare it against |
We tested the detector separately in is Copyleaks accurate, and unpacked the report itself in what a Copyleaks AI content score means.
The number behind the number
Where the .03 percent false-positive claim comes from
Copyleaks publishes per-language accuracy for its current model, and the two columns do very different jobs. The human column is the false-positive complement, which is where the headline claim is drawn from. The AI column is recall, and it moves far more.
| Language | Human text read correctly | AI text caught | What that implies |
|---|---|---|---|
| English | 99.97% | 99.20% | The source of the industry-low .03% false-positive headline |
| Spanish | 99.85% | 98.02% | Human accuracy implies roughly 1 in 667 clean documents flagged |
| French | 99.88% | 96.18% | Nearly 4 percent of AI text reads as human |
| Italian | 99.88% | 97.00% | Same human accuracy as French, better AI recall |
| German | 99.94% | 95.63% | Strongest human accuracy after English, weakest but one on AI |
| Portuguese | 99.95% | 93.08% | Almost 7 percent of AI text goes undetected, the widest gap published |
Read the table as a whole and the shape is clear: Copyleaks tunes hard against false positives and accepts a wider miss rate on AI text, and it does that most successfully in English. That is a defensible design choice for a product sold to institutions, because a wrong accusation costs more than a missed one. It is also why the number gets quoted at you as though it were a measurement of your document rather than an average over a test set.
The comparison
Six AI humanizers people buy for Copyleaks, side by side
Entry price is each vendor's cheapest paid plan. Where the yearly rate is cheaper we lead with it and put the monthly figure in brackets, because that is the number buyers actually compare.
| Tool | Entry price | Volume | Copyleaks position | Free tier | Best for |
|---|---|---|---|---|---|
| Undetected.ai | $9/mo yearly ($12 monthly) | 15,000 words/mo on Starter, 80,000 on Pro, 250,000 at $39 | No Copyleaks claim: we have no access to it. We rewrite the predictability and rhythm its classifier reads | Free account: 3 runs a day, 9,000 words a month | Anyone whose work gets scanned inside an LMS or a Google Doc without warning |
| Undetectable.ai | $5/mo yearly ($9.99 monthly, $60/yr) | 10,000 words/mo on the entry tier, 20,000 at $9.50/mo yearly | Names Copyleaks in its marketing and ships an in-house detector for pre-checks | Yes, a 250-word trial | Buyers who want the cheapest annual price from the best-known brand |
| WriteHuman | $12/mo yearly ($18 monthly) | 80 requests/mo at up to 600 words each on Basic, unlimited on Ultra | Lists Copyleaks by name and bundles its own detector next to the humanizer | Yes, 3 requests/mo at 250 words | Writers filing a few long pieces rather than a steady stream of short ones |
| Walter Writes AI | $8/mo billed yearly ($96/yr) | 30,000 words/mo on Starter with a 750-word cap per request, 70,000 on Pro | Reports an in-house detection score rather than proof against Copyleaks itself | Free usage offered, limit not published | High monthly word counts on a small budget, if the request cap suits you |
| BypassGPT / HIX Bypass | $8/mo yearly on promo ($12 monthly), read July 14, 2026 | 5,000 words/mo on Basic, 30,000 on Pro | Names Copyleaks explicitly along with Turnitin, GPTZero, Originality.ai, ZeroGPT and Winston | Yes, 150 words/mo | Buyers who want to see output quality before paying anything |
| QuillBot | $8.33/mo yearly ($19.95 monthly), read July 16, 2026 | Unlimited paraphrasing on Premium, humanizer capped on free | Makes no claim about Copyleaks, and paraphrasing alone rarely moves a detector reading | Yes, 125 words per paraphrase | Writers who want rewriting and grammar help, not detector clearance |
We build one of these tools, so read our row with that in mind. The rest of the page is where the others beat us.
Tool by tool
What each one is actually good at
Undetected.ai
The rewrite rebuilds sentences rather than swapping synonyms, which matters here because a Copyleaks report arrives with a similarity score attached and paraphrasing lifts that half. Our own AI-pattern score shows what changed, with its reasons.
Best for: Anyone whose work gets scanned inside an LMS or a Google Doc without warning.
From: $9/mo yearly ($12 monthly).
Undetectable.ai
The most established product in the category, with writing-style matching, unlimited detection checks and an API on every tier. Billed yearly it is the cheapest option on this page by a wide margin, though you get 10,000 words a month against our 15,000.
Best for: Buyers who want the cheapest annual price from the best-known brand.
From: $5/mo yearly ($9.99 monthly, $60/yr).
WriteHuman
Meters by request instead of by word, which is cheaper if you file a handful of long documents a month. It is also the only tool here shipping an MCP server, so an AI agent can call it as a tool inside a writing workflow.
Best for: Writers filing a few long pieces rather than a steady stream of short ones.
From: $12/mo yearly ($18 monthly).
Walter Writes AI
The most words per dollar here and an interface in 80-plus languages, but the 750-word cap per request on the entry plan means a 3,000-word essay is split into four passes, and the seams between passes are where tone drifts.
Best for: High monthly word counts on a small budget, if the request cap suits you.
From: $8/mo billed yearly ($96/yr).
BypassGPT / HIX Bypass
The most specific detector claims in the category and a genuine free allowance, though 150 words is a taste test rather than a work session. Its pricing page sits behind a Cloudflare check we could not read this month, so treat the price above as a July 14 snapshot.
Best for: Buyers who want to see output quality before paying anything.
From: $8/mo yearly on promo ($12 monthly), read July 14, 2026.
QuillBot
A full writing suite with nine paraphrase modes, a plagiarism checker and citation tools. It is a good writing product that happens to include a humanizer, and it is honest enough not to promise you a detector result.
Best for: Writers who want rewriting and grammar help, not detector clearance.
From: $8.33/mo yearly ($19.95 monthly), read July 16, 2026.
How to choose
Six things that decide whether a humanizer holds up in a Copyleaks report
Price is the easiest thing to compare and the least useful. These are the differences that show up the first time someone forwards you the report.
1. Does it move the AI score without lifting the similarity score?
This is the Copyleaks-specific trap and almost nobody warns you about it. The two numbers in the report are calculated independently, and the cheapest way to change your prose, swapping words and reordering clauses around a source you are close to, is exactly the behaviour the similarity engine is built to catch. You can trade an AI flag for a plagiarism flag in a single pass and end up in a worse conversation than the one you started in. Judge a tool on both numbers, not the one it advertises.
2. Rebuilt sentences, not swapped words
The classifier reads how predictable each sentence is and how much the rhythm varies across a document. A tool that replaces words with rarer synonyms leaves both properties untouched, so the reading barely moves while your prose starts sounding like a thesaurus fell on it. Test any candidate on a paragraph you know well and ask a simple question: were the sentences rebuilt, or just repainted? You can usually tell by reading two of them aloud.
3. Does your meaning survive the pass?
Cheap tools fail hardest here, and the damage is quiet. "Fell 40 percent" becomes "fell noticeably" and your evidence is gone, a cited author's name gets swapped for a near-synonym, or a quoted passage stops matching its source, which is its own problem in a document that is also being similarity-checked. Paste in a paragraph with numbers, names and citations, then check every one survived. A clean detector reading on mangled copy is worth less than no rewrite at all.
4. Can you check the result before it is submitted?
Copyleaks is usually run by someone else, inside a system you do not control, which makes it different from a detector you can open in a second tab. New Copyleaks accounts do get a limited free credit allowance, so a pre-check is possible, but you are metering it against a suite priced for institutions rather than individuals. No humanizer can show you a Copyleaks number before you submit, ours included, because nobody outside Copyleaks can read one. What a tool can honestly give you is its own measure of the rewrite and the reasons behind it, so you spend a scan credit once on a draft you have already looked at rather than three times on guesses.
5. One pass, or a detector at a time?
Detectors weight signals differently, so a rewrite tuned for Copyleaks can still come back with a Turnitin percentage or a GPTZero flag. Institutions rarely standardise on one checker, and the department that scans your next submission is not always the one that scanned your last. If a tool targets a single detector you end up rerunning text until something passes, and each extra pass costs you more meaning. Test any candidate against two or three, not only the one it recommends.
The ten-minute test
Take 400 words of something real you wrote, not a sample paragraph from a demo. Run it through any tool you are considering. Check every number, name and citation survived. Read the output aloud and ask whether someone who knows your writing would notice. If it sounds like you and the facts are intact, you have your answer, and you did not need anyone's review to get it.
Being straight with you
What no humanizer can do, and where the others beat us
Nobody can promise you a Copyleaks number. The model is retrained, and on enterprise deployments the sensitivity threshold is a setting the institution controls, so the same paragraph can genuinely read differently at two schools running the same product. What a humanizer can honestly claim is that it changes the statistical properties the classifier measures. Copyleaks itself frames the output as a signal for review, and institutional guidance published by colleges using it says the result "should be used as one data point among many, not as standalone evidence."
The .03 percent claim deserves context, in both directions. It is a real published figure and it is the lowest in the category, which is to Copyleaks' credit: a detector sold into education should tune against wrong accusations. But it is drawn from the vendor's own English test set, and independent testing of AI detectors on real-world writing lands nearer 85 to 90 percent accuracy with false positives in the 8 to 15 percent range. A Stanford study found 61.3 percent of essays by non-native English speakers were wrongly flagged. If you write in English as a second language, the headline number is not describing you.
A rewrite does nothing to a document history. Google Docs version history, Grammarly Authorship and Word revision tracking all record how a document was composed, and Copyleaks itself sells a Google Docs add-on that scans from inside the file. Those are provenance records, and no rewriting tool edits them. Drafting inside a shared doc is the cheapest insurance there is, because a visible edit trail settles the question in a way no score can.
We do have a free account, and it is small on purpose. Three runs a day of up to 1,500 words, 9,000 words a month, no card. Anyone can also run the demo on this page twice a day without an account at all. Paid plans are planned from $9 a month for 15,000 words and are not on sale yet. If your budget is genuinely zero, BypassGPT's 150 free words a month or WriteHuman's three free requests will serve you better than we will, and QuillBot's free paraphraser is more generous than either.
On price alone, Undetectable.ai wins. About $5 a month billed annually undercuts everything on this page, and it is the most established product in the category with a wider feature surface than ours. It gives 10,000 words a month against our 15,000 at $9, so weigh the two numbers together rather than reading the headline price on its own. We wrote up their full pricing including cost per 1,000 words if you want the arithmetic.
For a large backlog on a small budget, look at Walter Writes. Its $8 yearly plan carries 30,000 words a month, more than triple ours per dollar, which matters if you are working through a semester of documents. The catch is the 750-word cap per request on that tier and an in-house score in place of proof against outside detectors.
And a warning about pages like this one. Nearly all of page one for this query is written by humanizer vendors, and every one of them ranks itself first. We are a vendor too, which is why this page publishes competitor prices we read ourselves with the date attached, marks the row we could not verify this month, and says plainly where the others win. The only comparison that settles it is the one you run on your own paragraph.
Good questions
Questions people ask about humanizers and Copyleaks
What is the best AI humanizer for Copyleaks?
The best AI humanizer for Copyleaks is one that rewrites for several detectors at once, because a Copyleaks report almost never arrives alone: the same scan returns a similarity score, and often a grammar grade, to the same reviewer. Undetected.ai rewrites in one pass and shows our own AI-pattern score before and after, from $9 a month for 15,000 words. Undetectable.ai is cheapest at about $5 a month billed yearly. WriteHuman meters by request, which suits long documents.
Does Copyleaks have a humanizer?
No. Copyleaks sells detection and content-integrity tools only: an AI text detector, AI image and video detectors, a deepfake detector, a plagiarism checker, text moderation and a grammar checker, plus an API, LMS integrations, a browser extension and a Google Docs add-on. Nothing in the product line rewrites your prose. That is why searches for a Copyleaks humanizer land on third-party tools like the ones compared here.
How much does Copyleaks cost?
Read off its own pricing page on July 26, 2026, the Copyleaks Personal plan is $13.99 a month billed annually ($167.88 a year) or $16.99 monthly. Pro is $74.99 a month billed annually ($899.88 a year) or $99.99 monthly. Billing runs on unified credits, where one credit scans 250 words or one image, so Personal carries 300,000 words a year and Pro carries 3,000,000.
How accurate is Copyleaks?
Copyleaks publishes over 99 percent accuracy and an industry-low .03 percent false-positive rate, which comes from its own English test set: its published table shows 99.97 percent human accuracy in English but 99.20 percent AI recall, dropping to 93.08 percent in Portuguese. Independent testing of AI detectors on real-world writing lands nearer 85 to 90 percent, with false positives in the 8 to 15 percent range.
Can an AI humanizer bypass Copyleaks?
A deep rewrite changes what the classifier measures, which is the property the AI score is built on: how predictable each sentence is and how evenly the rhythm runs across the document. A synonym swap does not, because it leaves both intact, and it actively raises the similarity score in the same report. No tool can promise a number, ours included: we have no access to Copyleaks, cannot see what it returns for your document, and do not predict it. Copyleaks itself frames the score as a signal for human review.
Why does Copyleaks say everything is AI?
Because the percentage is not a confidence score. It is the proportion of the document Copyleaks flagged as likely AI-generated, so a clean paragraph sitting inside a flagged section gets counted too. Short submissions make this worse: the web platform needs 255 characters minimum and the browser extension 350, and readings near those floors are the least stable ones the tool produces.
How do I reduce my Copyleaks AI content score?
Rebuild the sentences rather than swapping words. The classifier reads sentence-level predictability and rhythm variation, so restructuring how a point is made moves the reading while a thesaurus pass does not. Watch the similarity score at the same time, since paraphrasing around a source is exactly what lifts it. If the flag is wrong, your drafts and document history settle it faster than any rewrite.
Go deeper
Related reading
Clear an AI detection flag
The humanizer page for text you are about to submit.
Copyleaks AI content score
What the percentage counts, and why it is not a confidence score.
Is Copyleaks accurate?
Vendor claims against independent testing, and the false-positive picture.
Best AI humanizer overall
The full comparison, beyond any single detector.
Run the test on something you actually wrote
Paste 400 words of real work, watch the gauge, then check your numbers, names and citations survived. That is the only comparison that decides this.
Meaning kept · Your own text rewritten · Saved to your history, delete any time