There are well over a dozen AI humanizers on the market right now, and every one of them claims to be the best. Most are variations on the same idea: paste text in, get a paraphrased version out, hope it passes a detector. That approach worked in 2024. It does not work in 2026. Detectors have gotten better, readers have gotten more skeptical, and the gap between "paraphrased AI slop" and "genuinely human-sounding prose" has widened into a canyon.
This guide compares twelve AI humanizers in depth: what each one actually is, how it charges you, where it is strong, where it falls short, and who it fits. One disclosure before we start: Metric37 is our product, so we are not a neutral referee. We have tried to keep every claim about competitors verifiable from their own sites, and we state our evaluation criteria up front so you can apply them yourself.
How We Evaluated These Tools
We did not run a staged bypass test and crown a winner from a single screenshot. Detector results vary by input text, by detector version, and by the day you run them, which is why "passes all detectors" badges are close to meaningless. Instead, this comparison is built on five criteria you can check for any tool, using its own free tier and published pricing:
- Output quality. Does the rewritten text read like a person wrote it, or like a thesaurus attacked it? Good humanization changes sentence structure and rhythm, not just vocabulary. Bad humanization preserves the AI skeleton and swaps the words, which fools nobody for long.
- Scoring and feedback. Does the tool tell you how good the output is, or do you have to guess? A humanizer without scoring is a slot machine. A humanizer with scoring is a workflow, because a number gives you a target and tells you when to stop.
- Pricing model. Subscription, credits, or one-time purchase? Monthly subscriptions punish occasional users, who pay for capacity they never use. Word packs and credits punish heavy users if the per-word rate is high. The right model depends on your volume, so we note which model each tool uses.
- Word limits. The headline price rarely tells the whole story. Per-request caps, monthly allowances, and trial limits decide whether a tool handles your actual documents or forces you to chop a 2,000-word article into fragments.
- Revision capability. First passes are rarely final. Can you iterate on an output, compare attempts, and keep earlier versions? Or does every retry overwrite the last one and burn more credits?
Pricing below reflects what each vendor published at the time of writing. Several tools advertise annual-billing rates as their headline monthly price, so always check the billing toggle before you enter a card number.
The 12 Tools at a Glance
| Tool | Approach | Scoring | Revisions | Free tier | Pricing model |
|---|
| Metric37 | LLM rewrite + quality gate | Unlimited, free | Version history + diffs | 1,500 words (signup) | One-time word packs, from $2 |
| Undetectable AI | Single-pass paraphrase | Built-in detector check | None | ~250-word trial | Subscription, word tiers |
| WriteHuman | Single-pass paraphrase | None | None | Limited trial | Subscription, per-request |
| StealthWriter | Detector bypass focus | None | Multiple variants per run | Limited trial | Subscription |
| QuillBot | Paraphrasing modes | None | None | 125 words/paste | Subscription (suite) |
| Humbot | Single-pass paraphrase | Built-in detector check | None | Small trial | Subscription, word tiers |
| HIX Bypass | Single-pass, multiple modes | Built-in detector check | None | Small trial | Subscription, word tiers |
| Netus AI | Multi-mode paraphrase | Built-in detector check | None | Limited trial | Subscription |
| BypassGPT | Single-pass, multiple modes | Built-in detector check | None | 150 words/month | Subscription, word tiers |
| Phrasly | Humanizer + detector combo | Unlimited detector | None | A few hundred words | Subscription + day pass |
| Smodin | All-in-one writing suite | Built-in detector | None | Daily free allowance | Subscription (suite) |
| Walter Writes AI | Humanizer + detector combo | Built-in detector | None | 300-word trial | Subscription, word tiers |
The Reviews
1. Metric37
Full disclosure again: Metric37 is the product behind this blog, so read this section as a maker explaining design choices, not as an impartial verdict. Metric37 is an LLM-based rewriter built around a feedback loop. Every rewrite is scored from 0 to 100 for how human it reads, and if a rewrite comes back below the quality bar, the system retries before showing it to you. You can re-score any text for free, as often as you want, including text you edited by hand.
Pricing: no subscription. One-time word packs start at $2 for 3,000 words and go up to $39 for 200,000 words. Packs never expire. The free tier is 1,500 words on signup with no credit card.
Strengths: the scoring loop and version history. You get up to 20 versions per document with word-level diffs between any two, and you can branch from any version to try a different tone. There is also a REST API for programmatic use, which most tools in this list do not offer. Because scoring is free and unlimited, the iterate-until-good workflow does not burn through your word balance.
Weaknesses: no unlimited plan, so extremely high-volume users who prefer a flat monthly fee will not find one here. The tool is focused on English prose; if you need humanization across dozens of languages, suite tools cover more ground.
Who it fits: writers, freelancers, and content teams who care about output quality and want a number to verify it, and anyone allergic to subscriptions.
2. Undetectable AI
Undetectable AI is probably the most heavily marketed humanizer on the market. It is a single-pass paraphraser with readability and purpose settings, plus a built-in multi-detector check that shows how your text scores against popular detectors.
Pricing: subscription tiers priced by monthly word allowance, with an entry tier around ten dollars per month and discounts on annual billing. The free trial covers only about 250 words.
Strengths: the bundled detector check is genuinely convenient. You see immediately whether the output trips the common detectors instead of pasting it into a second tool. The interface is simple and fast, and the brand recognition means plenty of tutorials and reviews exist if you get stuck.
Weaknesses: it is a one-shot tool. If the output reads awkwardly, your only option is to run it again and hope, and each run consumes words from your monthly allowance. There is no version history, no diff view, and no way to score your own edits. The output also tends toward a flat, careful register that loses the original's energy.
Who it fits: people who want a quick detector check and a one-click rewrite, and who do not plan to iterate.
3. WriteHuman
WriteHuman is a streamlined paraphraser with a clean interface and a request-based pricing model. You submit text, it returns a humanized version, and that is essentially the whole product.
Pricing: subscription plans metered by number of requests rather than words, with a cap on words per request that rises with the plan tier. Entry plans are in the low teens per month, with cheaper annual rates.
Strengths: simplicity. There is almost no learning curve, and the per-request model is easy to reason about if your documents are consistently sized.
Weaknesses: the per-request model cuts the other way for long documents, since a 2,500-word article can exceed the per-request cap on lower tiers and force you to split it. There is no quality scoring, so you cannot tell whether an output is good without reading it cold, and there is no revision tooling at all. A retry is just another request against your monthly quota.
Who it fits: users with short, uniform documents who value a minimal interface over workflow features.
4. StealthWriter
StealthWriter is built squarely around detector evasion. It generates multiple alternative versions of each rewrite and lets you swap individual sentences between them, which is a more granular workflow than most single-pass tools offer.
Pricing: subscription only, and published plan prices have varied between roughly twenty and thirty-five dollars per month depending on tier and billing period. There is no meaningful free tier beyond a small trial.
Strengths: the multiple-variants approach. Getting several candidate rewrites at once and stitching the best sentences together gives you more control than a single take-it-or-leave-it output.
Weaknesses: the focus on evasion over readability shows in the prose, which can come out stilted. It is also one of the pricier options for what is functionally a paraphraser, and sentence stitching by hand is slow at volume.
Who it fits: hands-on editors who want to assemble a rewrite sentence by sentence and are less price-sensitive.
5. QuillBot
QuillBot is the elder statesman of paraphrasing. It predates the AI-detection arms race entirely, and it shows: QuillBot is a writing suite with paraphrasing modes, a grammar checker, a summarizer, and translation, not a purpose-built humanizer.
Pricing: freemium subscription. The free tier is genuinely useful for short passages but caps paraphrasing at 125 words per paste. Premium unlocks longer inputs and more modes at around twenty dollars on monthly billing, dropping to roughly eight dollars per month if you pay for a year up front.
Strengths: sentence-level control. You can click individual words for synonym alternatives and choose between modes like Formal, Simple, and Creative. As a rephrasing aid inside a human editing workflow, it is polished and reliable.
Weaknesses: it was never designed to make AI text read human, and synonym-level changes do not alter the structural patterns detectors flag. Run obvious AI text through QuillBot and you usually get obvious AI text with fancier vocabulary.
Who it fits: students and professionals who want a general-purpose editing assistant and are doing the actual humanization themselves.
6. Humbot
Humbot is a straightforward single-pass humanizer with an integrated AI checker, positioned on speed and simplicity. Subscriptions are priced by monthly word allowance, with entry pricing around fifteen dollars per month, the usual annual discount, and a small free trial in the range of a few hundred words.
Strengths: the built-in checker closes the loop between rewriting and verifying in one screen, and the tool is fast. For short-form content like product descriptions or social posts, the paste-click-copy flow is about as low-friction as it gets.
Weaknesses: no revision features, no quality scoring beyond the binary detector check, and output quality on longer, more nuanced text is inconsistent. Like most single-pass tools, when it misses, your only recourse is to spend more words on another spin.
Who it fits: high-frequency, short-form use where speed matters more than voice.
7. HIX Bypass
HIX Bypass is the humanizer arm of the HIX AI writing suite. It offers multiple rewriting modes (from fast to aggressive) and bundles detector checks against the well-known detection tools.
Pricing: subscription tiers by monthly word allowance. Published entry pricing has ranged from around ten to twenty dollars per month depending on words and billing period.
Strengths: the mode system gives you some control over how heavily the text is transformed, which is more flexibility than most one-button competitors. If you already use other HIX tools, the suite integration is convenient.
Weaknesses: heavier modes trade away readability, and experimenting across modes is manual copy-paste work. The per-word cost at lower tiers is on the high side for a single-pass tool.
Who it fits: existing HIX suite users, and people who want a transformation-intensity dial.
8. Netus AI
Netus AI is a multi-mode paraphraser that pairs a bypass-oriented rewriter with its own detector. It markets fine-tuned paraphrasing models rather than a thin wrapper over a general-purpose LLM, sold as a subscription with published tier prices clustering around twenty dollars per month, higher tiers for volume, and a limited trial.
Strengths: mode variety, and the paired detector-plus-paraphraser loop within a single interface. Output on medium-length text is serviceable.
Weaknesses: the same structural gap as its single-pass peers: no quality score, no revisions, no diffs, so you cannot systematically improve a borderline output. Documentation and public detail about the product are thinner than for the bigger names, which makes its claims harder to evaluate before paying.
Who it fits: users who want a detector and rewriter in one tool and are comfortable evaluating output quality by eye.
9. BypassGPT
BypassGPT does what the name says: it is positioned almost entirely on getting AI text past detectors. It offers several rewriting modes (fast, creative, enhanced) and a built-in AI checker.
Pricing: subscription tiers by monthly word allowance, starting around twelve dollars per month, with tiers stepping up through capped plans to an unlimited plan. The free plan is tiny: on the order of 150 words per month, with a low per-request cap that fits about a paragraph.
Strengths: mode options and an unlimited top tier, which flat-rate fans will appreciate. The built-in checker keeps the verify step in-house.
Weaknesses: the free tier is too small to evaluate the tool on a real document before paying, which matters for a product whose entire pitch is output you have to judge by eye. There is no quality scoring or revision system, and the evasion-first framing means readability is not the priority.
Who it fits: volume users focused narrowly on detector results who want an unlimited plan.
10. Phrasly
Phrasly pairs a humanizer with an unlimited free AI detector, and is popular with students. It advertises keyword retention during humanization, which matters if your text has terms that must survive the rewrite.
Pricing: freemium. The free plan includes a small humanization allowance (a few hundred AI words) plus unlimited detection. The unlimited plan runs about twenty dollars on monthly billing, roughly half that on annual, and there is a cheap multi-day access pass if you just need to get through one deadline. Paid plans allow long inputs, up to several thousand words per request.
Strengths: the unlimited free detector earns its keep even if you never pay, and the day-pass option is a rare nod to people who do not want another subscription. Large per-request limits handle full essays without splitting.
Weaknesses: humanization itself is still single pass with no scoring or version history, and the free humanization allowance is too small to test more than a couple of paragraphs.
Who it fits: students and occasional users, especially those who mainly need the detector and only sometimes the rewriter.
11. Smodin
Smodin is not a dedicated humanizer at all; it is an all-in-one writing platform with an AI writer, rewriter, humanizer, detector, plagiarism checker, summarizer, and translation across 100+ languages. The humanizer is one tool among many, and it shares its engine with the rewriter.
Pricing: freemium subscription suite. There is a limited free daily allowance, and paid plans span roughly ten to thirty dollars per month depending on which tool bundle you need.
Strengths: breadth. If you want one subscription that covers drafting, rewriting, checking, and translating, Smodin consolidates tools you would otherwise juggle across three tabs. The multilingual support is wider than anything else on this list.
Weaknesses: a humanizer that is also a rewriter that is also a spinner is a generalist, and it reads like one. The output is closer to classic paraphrasing than to structural humanization, and there is no scoring loop or revision tooling. Jack of all trades applies.
Who it fits: students and multilingual users who value an all-in-one toolbox over best-in-class humanization.
12. Walter Writes AI
Walter Writes AI is a newer entrant that combines a humanizer with its own detector, tone controls, and support for 80+ languages. It has been building a profile fast through aggressive content marketing.
Pricing: subscription tiers by monthly word allowance, advertised from around eight dollars per month at the entry tier on annual billing, scaling through capped tiers to a high-volume team plan. Per-request caps apply, from 750 words on the entry tier up to about 2,000 on the top tiers. There is a 300-word free trial with no signup. Note that the headline prices are annual-billing rates, so check the billing period before subscribing; this is a recurring theme in user reviews.
Strengths: tone controls and broad language support at a competitive entry price, plus a no-signup trial that lets you sanity-check the output instantly.
Weaknesses: no version history or free re-scoring, and the 300-word trial is too short to judge performance on a full article. As with several tools here, the built-in detector grading its own homework is not independent verification.
Who it fits: budget-conscious users who want tone control and multilingual coverage and are comfortable with annual billing.
Why Single-Pass Paraphrasing Falls Short
Nine of the twelve tools above share the same fundamental design: you paste text, click a button, and get one output. If it does not work, you paste again and hope for something different. This is the slot machine from the criteria section: pull the lever again and hope.
The problem is that single-pass rewriting often leaves the underlying statistical patterns of AI text intact. Sentence lengths stay uniform. Transitions stay predictable. The "shape" of the text remains AI-shaped even when individual words change. That is why paraphrased AI text so often still trips detectors, and why it still reads flat to a human even when it sneaks past one. For a deeper look at what detectors actually measure, see our guide to how AI detection works.
The Scoring Feedback Loop
The single biggest differentiator in this comparison is whether a tool tells you how good the output is. Without scoring, you are guessing. With scoring, you have a concrete number to work toward.
Most tools approximate this with a built-in detector check, which is a binary signal: flagged or not flagged. That tells you nothing about why a borderline text is borderline or what to fix. A graded score changes the workflow. Metric37 grades every rewrite from 0 to 100, and because checking a score costs nothing, you can rewrite, check, edit one sentence, check again, and keep going until you are satisfied. The jump from a 65 to an 85 is not about running the same button again; it is about finding which parts still read synthetic and fixing those.
Whatever tool you pick, do not rely on its built-in checker as your only verification. An independent check, like our free AI detector, costs nothing and removes the conflict of interest of a tool grading its own output.
Revision Capability: Versions, Diffs, and Branching
When you improve a piece of text, you want to compare where you started with where you are. You want to see what changed between attempt two and attempt four, and you want to try a different tone without losing what you had.
Almost no humanizer supports this. The standard experience is one output box that gets overwritten on every run. StealthWriter's multiple variants are a partial exception, and the version history described in Metric37's review above was built for exactly this problem: every attempt is kept, any two can be compared, and you can branch off whichever one worked. For one-off jobs this barely matters. For anyone producing content regularly, it is the difference between a tool and a workflow: a tool gives you one result, a workflow helps you produce good results repeatedly.
Pricing Models: Subscriptions vs Word Packs
Eleven of the twelve tools here are subscriptions. That model is great for the vendor and fine for users with steady monthly volume, but most people's humanization needs are spiky: heavy during a product launch or exam season, near zero in between. With a subscription, the quiet months are pure waste, and the annual-billing-as-headline-price trick makes the waste bigger than it looks.
Metric37 deliberately went the other way: pay-once word packs (the exact tiers are in the review above) that never expire. You buy capacity when you need it and it waits for you when you do not. We think this is the honest model for this category, but the math is checkable either way: estimate your real monthly word volume, divide each tool's monthly price by it, and compare the per-word cost against a pack you might buy twice a year.
Free tiers deserve the same scrutiny. Most competitors cap free usage at 150 to 300 words as a one-time taste, which is not enough to evaluate output quality on a real document. Metric37's free tier is 1,500 words on signup; Phrasly's unlimited free detector and Walter Writes' no-signup trial also stand out as free offerings with real utility.
Word Limits: The Fine Print That Matters
Two limits trip people up. The first is the monthly allowance, which is what the pricing page advertises. The second is the per-request cap, which is buried in the fine print and decides whether your 3,000-word article goes through whole or has to be split into chunks. Splitting is not just annoying; it produces worse output, because the rewriter loses the document-level context that keeps terminology and tone consistent across sections.
WriteHuman's lower tiers cap requests at several hundred words. BypassGPT's free tier caps near a single paragraph. Walter Writes caps requests at 750 words on its entry tier and around 2,000 words even at the top. If you regularly work with long-form content, check the per-request number before the monthly one.
API Access
If you need to humanize content programmatically, the field narrows fast. Most of the tools in this list are web-only. Undetectable AI and Phrasly offer APIs aimed at businesses, and Metric37 provides a REST API with API key authentication that returns rewritten text along with its quality score, so automated pipelines get the same verify step as the web app. See the API documentation for endpoints and authentication details.
Which Tool for Which Job
No single tool is right for everyone, and the honest answer depends on what you are producing. We have written focused breakdowns for the four most common situations:
As a rough decision shortcut: if you need a one-off rewrite and a quick detector check, the single-pass tools with built-in checkers (Undetectable AI, Humbot, HIX Bypass, BypassGPT) all do the job. If you mainly need detection with occasional humanization, Phrasly's free detector is hard to argue with. If you want one subscription covering many writing tasks in many languages, Smodin or QuillBot make sense. If you produce content regularly and care whether the output is actually good, you want scoring and revisions, and that is the gap Metric37 was built to fill.
The Bottom Line
The best AI humanizer is the one that helps you produce writing a reader would choose to keep reading. Synonym swapping and single-pass paraphrasing solve yesterday's problem; the tools that matter now give you a feedback loop: rewrite, score, iterate, improve. Apply the five criteria from the top of this guide to whatever tool you are considering, and weigh our obvious bias accordingly when we say Metric37 is the only tool here that combines graded scoring, version history, and pay-once pricing, with a free tier large enough to prove it on a real document before you pay anything.