Independent review · prices read on undetectable.ai August 23, 2026
Undetectable AI Pro: an Undetectable AI review of the plans, the free trial and the subscription limits
There is no plan called Pro. Here is what the paid tiers are actually named, what each one costs, and which limit will bite you first.
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 ·
Written by Undetected.ai, a competing humanizer · every price quoted from the vendor's own page
The short answer
Undetectable.ai does not sell a plan named "Pro". Its paid plans are named by how many words you can humanize each month: 10,000 words for $9.99 a month or $5.00 a month charged annually, 20,000 for $19.00 or $9.50 yearly, 35,000 for $31.00 or $15.75 yearly, and 50,000 for $42.50 or $21.25, plus an unpriced "For Business" tier. The free trial is a one-time 250 words. Every paid tier advertises "Unlimited AI Detecting" and "Unlimited Human Auto Typer", but the humanizer itself, the thing you are paying for, is metered on all of them.
Last updated August 23, 2026. Loaded undetectable.ai/pricing three times that day; all three loads were identical.
The name nobody sells
Why "Undetectable AI Pro" returns nothing on their own site
About 590 US searches a month look for this plan. It has never existed under that name.
Most subscription software sells you a tier name. Basic, Plus, Pro, Enterprise. Undetectable.ai does not. Its pricing page lists four boxes headed 10K words/month, 20K words/month, 35K words/month and 50K words/month, then a fifth headed "For Business". No Pro anywhere on the page.
So when somebody types "Undetectable AI Pro" they mean one of two things, and it is worth knowing which you mean before you spend anything. Usually it means "the paid version, as opposed to the trial", in which case the answer is the ladder below and the cheapest rung is five dollars a month on annual billing. Occasionally it means "the top tier", in which case the honest answer is that the top tier is the For Business plan and its price is not published; you have to ask for it.
This matters more than a naming quibble because comparison articles in this niche invent the plan. If a page tells you what Undetectable AI Pro costs, it has either renamed one of the word tiers without telling you or it has copied another page that did. Neither is a number you should budget against.
The real ladder
Undetectable AI subscription plans and what each one costs
Both columns come off the same page. The left figure is what the plan lists at, the right is what annual billing brings it down to.
| Plan | Listed | On annual billing | Who it fits |
|---|---|---|---|
| 10,000 words a month | $9.99 | $5.00 a month, charged annually $60.00 | One student, one term. Two or three assignments a month with room to redo a paragraph. |
| 20,000 words a month | $19.00 | $9.50 a month, charged annually $114.00 | A freelance writer with a steady client or two, or a dissertation chapter at a time. |
| 35,000 words a month | $31.00 | $15.75 a month, charged annually $189.00 | A small content team publishing several times a week. |
| 50,000 words a month | $42.50 | $21.25 a month. This tier is marked "Includes all features from other plans" with "6 Months Free" and "Cancel Anytime". | An agency running client work through one account. |
| For Business | Not published | Custom pricing and plans. The closest thing to a "Pro" tier, and the one with no public number. | Bulk credits, non-expiring credits, redistribution and white labeling, priority support. |
Two things are worth pulling out of that table. The first is the size of the annual discount: it is close to half on every tier, which is aggressive even by this market's standards and tells you the company is optimising hard for twelve-month commitments. If you are buying for one dissertation or one launch, the monthly figure is the real one, and at $9.99 for 10,000 words it is no longer the cheapest option in the category.
The second is that the allowance is monthly and does not carry forward. Undetectable.ai says so implicitly on its business tier, which advertises "Non-expiring credits" as a feature you have to move up to get. On the consumer tiers, a quiet month is a month you paid for and did not use. That is normal in this industry, and it is the single most common reason people feel a plan is smaller than the number on the box.
For the full breakdown of every tier including per-word arithmetic, we keep a dedicated page on Undetectable.ai pricing. If you have already decided against them, the head-to-head sits on the Undetectable.ai alternative page.
Read the word 'unlimited' carefully
What is actually unlimited on an Undetectable AI subscription
Two things are. The one you came for is not.
Humanizing words
Capped on every tier
This is the thing you are buying, and it is the one number that is metered. 10,000, 20,000, 35,000 or 50,000 words a month depending on the plan.
AI Detecting
"Unlimited AI Detecting"
Listed against all four paid tiers. Scanning is cheap to give away because it is what creates demand for the rewrite.
Human Auto Typer
"Unlimited Human Auto Typer"
A separate product that replays text into a document as keystrokes. Listed as unlimited on every paid tier.
API access
"API compatible" on every paid tier
Genuinely better than us on this point. Most competitors gate programmatic access behind the top plan or sell it separately.
Free trial
250 words, once
The page states it plainly: "Free Trial is limited to 250 words. Additional usage requires paid plan activation."
Every one of the four consumer tiers carries the same seven-line feature list: "Passes AI detectors", "High quality, legible content", "Watermark and future proof", "Writing level matching", "API compatible", "Unlimited Human Auto Typer", "Unlimited AI Detecting". Read down it and you notice that the two items marked unlimited are the two items that are not the product. Detection is unlimited. Typing replay is unlimited. Rewriting, which is why you are on the page, is the number in the plan's name.
That is not a criticism unique to this vendor, it is how the whole category prices, and the pattern is worth learning because it repeats everywhere. We wrote up who really removes the word limit in AI humanizer plans with unlimited words, and the short version is that almost nobody does.
The API line deserves its own sentence because it is a real advantage and we would rather say so than quietly leave it out. "API compatible" appears against all four paid tiers, including the ten-dollar one. Most competitors, us included, do not put programmatic access on the entry plan. If you need to humanize inside a pipeline rather than in a browser tab, that alone may decide it.
The most interesting sentence on their pricing page
A refund tied to a detector result
"Money back guarantee. If anything we produce is flagged as not human, we will refund the cost of humanization."
undetectable.ai/pricing, read August 23, 2026
Almost nobody in this market attaches money to an outcome, and Undetectable.ai deserves credit for doing it. It is the closest thing to a warranty you will find here, and it is a fair reason to pick them over a vendor that promises the same result and stands behind none of it.
Read the scope, though. It refunds the cost of humanization, not the subscription, and the page sends you to its help centre for the conditions rather than setting them out in place. So it is a rebate on the specific runs that failed, not a guarantee that the month you bought was worth buying. Check those conditions before you rely on it, because a guarantee whose terms live on another page is a guarantee you have not actually read.
We do not offer an equivalent, and we are not going to pretend otherwise. We also do not claim a rewrite will clear any named detector, because detector vendors change their models without announcing it, Turnitin consolidated its ensemble into a single model in July 2026, and any promise about a third party's score has an expiry date nobody tells you. What we do instead is show our own AI-pattern reading before and after and name which patterns moved, which is a claim we can actually stand behind. The reasoning is set out on what it means for an AI humanizer to actually work.
Five rivals, honestly compared
Undetectable AI against the alternatives
Every price was read on the vendor's own page on the date in the last column. Where a vendor does not publish a number, this table says so instead of guessing.
| Tool | Entry paid price | How it meters you | Worth knowing | Checked |
|---|---|---|---|---|
| Undetectable.ai | $5.00/mo billed yearly ($60/yr) for 10,000 words | Metered by words per month. Four fixed tiers plus a custom business tier. | The only tool here that puts a REST API on its entry plan, and the only one offering a refund tied to a detector result. | Aug 23, 2026 |
| Walter Writes AI | $8/mo billed annually ($96/yr) for 30,000 words | Metered by words per month, with a per-request cap that rises with the tier: 750, 1,500, 2,000, 2,000 words. | Three times the entry word allowance of Undetectable.ai for three dollars more. Its per-request cap is the constraint, not the monthly one. We reviewed it in full separately. | Aug 23, 2026 |
| WriteHuman | $12/mo billed annually ($144/yr), 80 requests a month | Metered by requests, not words, with a word ceiling per request: 600 on Basic, 1,200 on Pro, 3,000 on Ultra. | Its Ultra tier at $36/mo annually is the only plan in this table advertising "Unlimited requests", and even that caps each request at 3,000 words. | Aug 23, 2026 |
| QuillBot Premium | Listed at $8.33/mo billed annually, but see the note | The humanizer becomes "No word or usage limit". Free is capped at 125 words and 6 uses a day. | Its Premium page rendered two different figures on the same load on Aug 23, and served a third on Aug 22. Verify at checkout, not from any review including this one. | Aug 23, 2026 |
| OpenAI, inside ChatGPT | Bundled with a ChatGPT account | Three modes: "Shorten text", "Improve clarity", "Make it original". No detector claim at all. | Carries the notice "Chats may be reviewed and used to improve our AI models", which rules it out for confidential drafts. | Aug 19, 2026 |
| Undetected.ai (us) | Planned at $9/mo yearly for 15,000 words | Metered by words per month, with a daily run cap so one afternoon cannot spend the month. | We show our own AI-pattern score before and after, and we refuse to promise a score at any named detector. Accounts are open; plans are not on sale yet. | Aug 23, 2026 |
Put the entry prices next to the entry allowances and the ranking changes. Undetectable.ai is cheapest to start at $5.00 a month billed yearly, but that buys 10,000 words. Walter Writes AI asks $8 a month billed annually and gives you 30,000. On a per-word basis that is roughly three times the value, and it is the comparison the price tags hide. Where Undetectable.ai pulls back ahead is the API on the entry tier and the refund sentence, neither of which Walter Writes matches.
WriteHuman meters differently again, by requests rather than words, which suits people who rewrite a few long documents and punishes people who rewrite many short ones. Its top tier is the only plan in the table advertising unlimited requests, and even there each request stops at 3,000 words.
Our own position is the one at the bottom of the table and we have put it there deliberately. We are not the cheapest and we do not have an API on the entry plan. What we do differently is refuse to sell the promise the rest of this market is built on. If that trade does not appeal, one of the tools above is a better buy and we would rather you found that out here than after a year's billing.
Buy it, or do not
Is Undetectable AI worth it at your volume
Buy the 10K plan if you are a student with two or three assignments a month and you want the cheapest annual price in the category. Ten thousand words is about four essays with room to redo paragraphs, and $60 for the year is less than most textbooks.
Skip it and look at Walter Writes if you write for a living. Above roughly 25,000 words a month the per-word arithmetic stops favouring Undetectable.ai, and paying $8 a month for 30,000 words instead of $15.75 for 35,000 is the obvious move unless you need the API.
Take the For Business route if credits expiring monthly is the thing that annoys you. Non-expiring credits, white labeling and redistribution only appear on that tier, and the price is a conversation rather than a page.
Do not buy anything yet if what you actually have is one flagged document. A false AI flag on writing you did yourself is a different problem from a word allowance, and rewriting is only one of the ways to answer it. We set out the others, including what a version history is worth, in how to prove you did not use AI, and the underlying numbers on how often detectors get this wrong are on the AI detector false positive rate.
Frequently asked
Undetectable AI Pro questions, answered
Is there an Undetectable AI Pro plan?
No. Undetectable.ai names its paid plans by monthly word volume rather than by tier name: 10K, 20K, 35K and 50K words a month, plus a custom "For Business" plan. Read on undetectable.ai/pricing on August 23, 2026. When people say "Undetectable AI Pro" they almost always mean any paid subscription, as distinct from the 250-word free trial.
How much does Undetectable AI cost?
The 10,000-word plan lists at $9.99 a month and drops to $5.00 a month charged annually, a $60.00 annual total. The ladder above it runs $19.00 or $9.50 yearly for 20,000 words, $31.00 or $15.75 yearly for 35,000, and $42.50 or $21.25 for 50,000. The business tier has no published price.
Undetectable AI Pro vs free: what is the difference?
The free trial is a one-time 250 words. Undetectable.ai states it directly: "Free Trial is limited to 250 words. Additional usage requires paid plan activation." A paid subscription buys you a monthly word allowance plus unlimited AI detecting, unlimited use of the Human Auto Typer, and API access. There is no ongoing free tier.
Does Undetectable AI Pro work?
It rewrites text and it runs its own multi-detector check, and it is one of the few vendors willing to attach money to the outcome: the pricing page offers to refund the cost of humanization if what it produces is flagged as not human. What nobody in this market can honestly promise is a specific score at a specific detector on a specific day, because detector models change without notice.
Is Undetectable AI legit?
It is a real, long-running product with a published price ladder, a stated refund policy and a public API, which is more than several competitors manage. Its own page claims 24,145,613 users and press coverage. Treat the user counter as marketing, treat the price ladder and the refund sentence as commitments you can hold it to.
Is Undetectable AI worth it?
At $5.00 a month billed yearly it is the cheapest entry price in this category, and 10,000 words a month covers a student comfortably. It stops being the obvious choice above about 30,000 words a month, where Walter Writes gives you three times the allowance for a few dollars more, and it is the wrong tool if you need one rewrite of one paragraph, where a free tier elsewhere will do.
Does Undetectable AI have a free trial?
Yes, and it is small and one-time: 250 words. That is roughly one paragraph. It is enough to judge whether the rewrite keeps your meaning, which is the only thing a trial that size can honestly tell you, and not enough to test how it handles a full document.
Why is Undetectable AI Pro not working?
The usual causes, in order: the monthly word allowance is spent, the 250-word free trial has been used, or the browser extension is out of date. Word allowances on this plan reset monthly and do not roll over, so a heavy week early in the cycle can leave nothing for the end of it. The company sells non-expiring credits only on its unpriced business tier.
What are the pros and cons of Undetectable AI?
For: the lowest annual entry price in the category, an API on every paid tier, unlimited detector scans, and a refund tied to a flagging outcome. Against: no ongoing free tier beyond 250 words, word allowances that expire monthly, marketing built entirely around beating detectors, and a business tier with no public price.
Is there an Undetectable AI promo code?
The pricing page itself carries the discount rather than a code: annual billing roughly halves the listed monthly figure on every tier, and the 50,000-word plan is marked "6 Months Free". Coupon sites in this niche mostly recycle the annual discount and present it as a code. Check the price at the checkout step before entering anything.
Does Undetectable AI offer a refund?
Its pricing page states: "Money back guarantee. If anything we produce is flagged as not human, we will refund the cost of humanization." That is unusually specific for this market and worth knowing before you buy, though it refunds the cost of the humanization rather than the subscription, and the page points you to its help centre for the conditions.
What is the best Undetectable AI alternative?
It depends which limit binds you. On monthly volume for the money, Walter Writes AI gives 30,000 words for $8 a month billed annually. On removing word limits entirely, QuillBot Premium is the only tool publishing "No word or usage limit" for humanizing. On a rewrite you can audit, we show our own AI-pattern score before and after and name what changed.
Keep reading
The questions behind this one
Undetectable AI pricing
Every tier with the cost per word worked out, and what the annual discount really saves you.
AI humanizer plans with unlimited words
Which plans really have no word limit, and what the ones advertising "unlimited" are actually counting.
Undetectable AI alternative
Where we differ, where they win, and which one to pick for the job you have.
QuillBot AI humanizer
The free tier with two caps instead of one, and what Premium removes.
Best AI humanizer
The paid field compared on price, allowance, data handling and what each vendor will promise.
How do AI detectors work?
The two signals every classifier reads, and why a 90 percent score does not mean what people think.
Before you commit to twelve months
Paste a paragraph here and watch which parts change and why. If Undetectable.ai is the better fit at your volume, buy it with our blessing.
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