Humanizer vs Undetectable AI vs StealthWriter (2026)
We make a fourth tool in this category, so read this with that in mind. Every price below was read from the vendor's own pricing page in July 2026 and is linked to its source. There are no bypass percentages here and the section explaining why is the most useful part of this page if you are comparing these tools anywhere else.
The short answer
10 humanizations + 10 scans a day, 1,000 words per input, no card.
Cheapest per word once you commit annually; scales to 50,000 words/mo.
200,000 words a month for $420/year — the highest ceiling of the four.
The only one of the four you can use without starting a subscription.
First, which “Humanizer”?
Worth clearing up, because it causes real confusion: several unrelated products in this category use almost the same name — HumanizerAI, Humanize AI, AI Humanizer, and a number of near-identical domains. They are different companies with different pricing. This page compares HumanizerAI (humanizerai.com), because that is the one whose pricing we could read directly. If you are comparing a different tool with a similar name, the numbers here will not apply to it, and you should check its own pricing page rather than trusting any comparison article — including this one.
Prices side by side
Competitor rows read from undetectable.ai/pricing, stealthwriter.ai and humanizerai.com in July 2026. All four of us change pricing without notice, so verify before you buy — a comparison table is stale the moment someone runs a promotion.
| StealthBypass | Undetectable AI | StealthWriter | HumanizerAI | |
|---|---|---|---|---|
| Free tier | 3/day, 500 words per run | 250-word trial total | 10/day + 10 scans, 1,000 words per input | Free AI score check |
| Entry paid plan | $4.99/mo — 5,000 words | $9.99/mo, or $5.00/mo annual — 10,000 words | $20/mo — 50/day, 5,000 words per input | $120/yr (~$10/mo) — 10,000 words |
| 10,000 words/mo costs | $9.99/mo (Pro) | $9.99/mo, or $5.00/mo annual | $20/mo (quota is per-day, not per-word) | $120/yr |
| Highest tier | 20,000 words/mo | 50,000 words/mo — $42.50/mo or $21.25 annual | $400/mo — 2,000/day | 200,000 words/mo — $420/yr |
| Use without subscribing | $1.99 / $4.99 credit packs | No | No | No |
| Built-in AI detector | Yes, every plan | Yes, unlimited | Yes, incl. free (V2 + Deep Scan) | Yes |
| Published bypass rate | None — see below | Treat any figure from any vendor with caution | ||
The $5 that is actually $9.99
Undetectable AI's “$5/mo” needs an annual commitment
Undetectable AI is widely quoted at “$5 a month”, and most comparison articles repeat it without qualification. That rate is the annualised price on their 10,000-word plan, billed as $60.00 for the year upfront. If you want to pay monthly and keep the ability to cancel, the same plan is $9.99 (checked July 2026).
This matters for an honest comparison of our own pricing too. At $9.99 month-to-month for 10,000 words, Undetectable AI is priced identically to StealthBypass Pro — $9.99 for 10,000 words. We are not cheaper at that tier. We are cheaper at the entry tier, where Lite is $4.99 for 5,000 words, and if you commit to a year they are cheaper than us.
Free tiers, ranked honestly
If you are trying to get work done without paying, this is the section that matters, and we come third of four.
- StealthWriter — 10 humanizations and 10 AI scans per day, 1,000 words per input, no card. This is a genuinely usable free tier, not a trial.
- HumanizerAI — free AI score checking, with humanizing behind a paid plan.
- StealthBypass — 3 rewrites a day at up to 500 words, with a detector score on each. Resets daily, so it is a real tier rather than a one-off, but the per-run limit is low.
- Undetectable AI — 250 words total, then you pay. That is a demo rather than a free tier.
Why there are no bypass percentages on this page
Almost every article comparing these tools ranks them by a detection bypass rate — 99% against Turnitin, 98% against GPTZero, and so on. Those numbers are close to meaningless, and we removed our own after publishing them.
A bypass rate only means anything if you know the exact corpus tested, the detector version, the pass threshold and the date. Even then it decays immediately, because Turnitin, GPTZero and Originality.ai retrain continuously and do not announce when. A permanent-looking percentage on a marketing page is either something that was never measured, or something that expired months ago. That applies to figures published about us as much as to figures we publish about anyone else.
The only test that tells you anything is the one you run on the text you actually care about, on the day you submit it. All four tools have a free tier or trial that lets you do exactly that.
How to choose
Work out roughly how many words a month you humanize, then pick on that alone — the feature lists are nearly identical and all four include a detector.
- Occasional, a few thousand words a term — a credit pack, or StealthWriter's free tier. Do not start a subscription for this.
- ~10,000 words a month, steady — Undetectable AI annual is the cheapest at $5.00/mo; month-to-month it is level with our Pro.
- Heavy daily use, long documents — StealthWriter, for the 5,000-word input ceiling and per-day allowances.
- Publishing at scale — HumanizerAI's 200,000 words/month tier is the highest ceiling here.
If you want the two head-to-head breakdowns in more depth, we have StealthBypass vs Undetectable AI and StealthBypass vs StealthWriter, plus wider surveys of StealthWriter alternatives, Undetectable AI alternatives and QuillBot alternatives.
Try StealthBypass free — 3 rewrites a day, no card →