AI humanizer comparison · Updated
The 5 Best Undetectable AI Alternatives in 2026
Undetectable AI is one of the best-known AI humanizers, but it is a word-metered subscription: $9.99/month buys 10,000 words, the free trial stops at 250 words, and its “money-back guarantee” is, in its own terms, a refund of credits with conditions. We compared the 5 alternatives people weigh against it most, on price, free limits, refund terms and what you get beyond the humanizer.
What is the best alternative to Undetectable AI?
For students, Conch is the most useful alternative: it rewrites AI-assisted drafts in 9 styles, including your own voice, checks text for AI patterns, and covers notes, flashcards and citations. QuillBot is the cheapest writing suite on a yearly plan, WriteHuman has the best free tier for short pieces, and Grammarly is the most cautious free option. No tool can promise a result on a detector it doesn't control.
- Best for students
- Conch: humanizer, AI checker and study tools in one
- Cheapest suite
- QuillBot: $99.95/yr with paraphraser and grammar
- Best free tier
- WriteHuman: 3 free requests a month
- Most cautious
- Grammarly: free basic humanizer, no sign-up
How we compared
Prices, word allowances, free tiers and guarantee terms were read from each tool's own pricing, product and terms pages in October 2026. QuillBot and Grammarly geo-redirect their pricing pages, so their US prices come from QuillBot's US pricing as listed in our QuillBot comparison and from current US reviews of Grammarly. We did not rank tools on detector scores: detectors change week to week, results depend on the text, and a bypass number shouldn't be the reason to pick a writing tool. Tools are ranked on value for a student who wants AI-assisted drafts to read naturally and in their own voice.
Read the guarantee before you pay
Most humanizers advertise a guarantee, and almost none of them is a plain refund. Undetectable AI's terms refund credits, not money, and only when a submission “provably flags as less than 75% human on a reputable AI detector”, claimed within 30 days. Cancelling forfeits unused words, and outside California and New York you cancel by email. GPTHuman's guarantee is a free rewrite. Phrasly refunds only if another tool's output scores more human than theirs, on 500+ words in its Ultra mode, within 14 days.
So the better question isn't which tool “passes” a detector this week. Ask which tool makes your draft read the way you actually write, at a price and on terms you can live with. Conch is built around that: Rewrite Mode keeps your meaning, can match your own writing voice, and sits next to the notes, flashcards and citation tools you need to actually understand what you hand in. Whatever you use, check your school's AI policy first.
Quick pick
Pick by what you need
- Humanizer plus study toolsConchRewrite in your own voice, check for AI patterns, then turn sources into notes and flashcards.
- Lowest yearly priceQuillBot$99.95 a year covers the humanizer, 9 paraphrase modes, grammar and a plagiarism check.
- A few short pieces a monthWriteHuman3 free requests a month, up to 250 words each, with a built-in detector.
- Free, light polishingGrammarlyBasic humanizing with no sign-up, from a tool that says plainly it isn't for bypassing detectors.
- Academic tone presetsGPTHumanStandard, College and PhD tones, and a Starter plan at $8.25/month billed yearly.
- A one-week deadlineConchThe 7-Day Assignment Pass is $7.99 once for 7 days of unlimited use, with no renewal.
The ranking
How they stack up
ConchOur pick
A humanizer, AI checker and study suite in one, built around keeping your own voice.
Pricing
Free; 7-Day Assignment Pass $7.99 one-time; Plus $15/mo; Unlimited $25/mo or $15/mo billed $180 yearly
Free tier
500 words a week for humanizing and AI checks, in 4 styles (Standard, Fluency, Natural, Simple).
AI generation
Rewrite Mode with 9 styles incl. Academic and your own writing voice, Magic mode, AI checks.
Pros
- Writes in your own voice, not a generic “human” tone
- 7-Day Assignment Pass: $7.99 once, no subscription
- Same account covers notes, flashcards, podcasts and citations
Cons
- Free plan is 500 words a week; Plus is 5,000 a week
- Citations and Magic mode are paid-only
- No detector-score guarantee (on purpose)
Best for: Students who want AI-assisted drafts to read naturally, and who also need notes, flashcards and citations for the same work.
Try Rewrite Mode free
QuillBot
A full writing suite whose AI humanizer comes with the paraphraser, grammar checker and plagiarism check.
Pricing
Free; Premium $19.95/mo, or $99.95/yr (≈$8.33/mo). US pricing.
Free tier
Humanize up to 100 words at a time with limited use; paraphrasing up to 100 words; limited AI detector.
AI generation
AI humanizer, 9 paraphrase modes plus custom modes, AI detector, 25,000 words/mo plagiarism check (Premium).
Pros
- Cheapest yearly price for a full writing suite
- Paraphraser, grammar, citations and plagiarism check included
- No bypass claims on its humanizer page
Cons
- Free humanizer stops at 100 words
- The humanizer is a side feature, not the main product
- No study tools (notes, flashcards)
Best for: Students who want one cheap yearly plan for paraphrasing, grammar, citations and humanizing.
Visit QuillBot →
WriteHuman
A dedicated humanizer with a real free tier and a sentence-level AI detector.
Pricing
Free; Basic $12/mo yearly ($20 monthly); Pro $19/mo yearly ($29); Ultra $39/mo yearly ($59).
Free tier
3 requests a month, up to 250 words each.
AI generation
Standard and Enhanced humanizing modes, 40+ languages, sentence-level AI detector, image detector.
Pros
- The most usable free tier of the dedicated humanizers
- Detector checks included on every plan
- Clear, published per-request limits
Cons
- Metered by requests: Basic allows 80 a month at 600 words each
- Refund policy isn't shown on the pricing page
- Humanizer only; no writing or study tools
Best for: Short pieces, like a discussion post or an email, where a few requests a month is enough.
Visit WriteHuman →
Grammarly
A free AI humanizer inside the grammar tool most students already have, with responsible framing.
Pricing
Free; Pro $12/mo billed annually, or $30/mo monthly (US).
Free tier
Basic humanizing with no sign-up; a free account adds 4 voices, custom voices and 6 languages.
AI generation
Humanizer agent with voice matching, grammar and tone checks, ~100 AI prompts/mo free; AI detector on paid plans.
Pros
- Free, with no sign-up for basic use
- Voice matching from your own writing samples
- Says plainly it isn't for bypassing detectors
Cons
- Free limits aren't spelled out
- The full humanizer needs Pro
- Pro costs more than most alternatives here
Best for: Polishing a draft so it sounds natural, inside a grammar workflow you already use.
Visit Grammarly →
GPTHuman
A humanizer with academic tone presets and clear monthly word allowances.
Pricing
Starter $8.25/mo yearly ($15 monthly, 25k words); Plus $14/mo yearly ($25, 60k); Unlimited $26/mo yearly ($49).
Free tier
A one-off 300-word trial.
AI generation
Standard, College and PhD tones; Balanced and Enhanced modes; detector, generator and paraphraser.
Pros
- Academic tone levels (College, PhD)
- Clear word allowances and per-request caps
- Cheap Starter plan when billed yearly
Cons
- Free trial is only 300 words, once
- Its “guarantee” is a free rewrite, not a refund
- Marketing leans hard on bypass claims
Best for: Students who mainly want tone presets for academic writing.
Visit GPTHuman →At a glance
Side by side
| Tool | Humanizer | AI checker | Grammar & paraphrasing | Study tools | Free tier | Starting price |
|---|---|---|---|---|---|---|
| Conch | ~ | 500 words/wk | $7.99 once | |||
| Undetectable AI | ~ | 250-word trial | $9.99/mo | |||
| QuillBot | 100 words | $99.95/yr | ||||
| WriteHuman | 3 requests/mo | $12/mo yearly | ||||
| Grammarly | ~ | Basic, no sign-up | $12/mo yearly | |||
| GPTHuman | ~ | 300-word trial | $8.25/mo yearly |
The verdict
Our recommendation
If all you want is a dedicated humanizer, WriteHuman's free tier is the easiest to try, GPTHuman has the most academic tone presets, and Undetectable AI is fine value on its annual plan, as long as you read its guarantee terms first. QuillBot is the best value if you also paraphrase and check grammar, and Grammarly's free humanizer is enough for light polishing.
For students, Conch is the strongest all-round pick. Rewrite Mode rewrites AI-assisted drafts in your own voice and checks them for AI patterns. The same account then turns your sources into notes, flashcards and citations, so you understand what you submit. It isn't the cheapest per word, and it won't promise a detector score, because no honest tool can.
FAQ
Frequently asked questions
Yes. Grammarly's AI humanizer has a free basic mode with no sign-up, WriteHuman gives 3 free requests a month (up to 250 words each), and QuillBot's free plan humanizes up to 100 words at a time. Conch's free plan includes 500 words a week for humanizing and AI checks, plus free study tools.
Undetectable AI starts at $9.99/month for 10,000 words, or $5/month billed $60 yearly. Larger plans cover 20,000 words ($19/month), 35,000 words ($31/month) and 50,000 words ($42.50/month), with 50% off when billed yearly. The free trial is limited to 250 words.
Yes, it is a real, working humanizer with paid plans and an AI detector. Read its terms before subscribing: the advertised guarantee is a refund of credits rather than money, unused words are lost when you cancel, and outside California and New York you have to cancel by email.
Yes, but it is small: the free trial is limited to 250 words. For a longer free test, WriteHuman gives 3 free requests a month of up to 250 words each, Grammarly's basic humanizer needs no sign-up, and Conch's free plan includes 500 words a week.
Its pricing page advertises one, but its terms describe a refund of credits, not money, and only if a submission provably scores less than 75% human on a reputable AI detector, claimed within 30 days. Cancelling forfeits remaining words.
No. Detectors change often and score each text differently, so no tool can honestly guarantee a result on a detector it doesn't control. Several humanizers advertise guarantees, but read the terms: most offer credits or a free rewrite, not a refund. It is safer to use AI as a drafting aid, rewrite in your own voice, and follow your school's AI policy.
Yes, if you want more than a humanizer. Conch's Rewrite Mode rewrites AI-assisted drafts in 9 styles, including an academic style and your own writing voice, and checks text for AI patterns. The same account covers notes, flashcards, podcasts and citations. Conch has a free plan, a $7.99 7-Day Assignment Pass, Plus at $15/month, and Unlimited at $25/month or $15/month billed $180 yearly.
For a full writing suite, QuillBot Premium at $99.95/year (about $8.33/month) is the cheapest here. Among dedicated humanizers, GPTHuman's Starter plan is $8.25/month billed yearly. For a single deadline, Conch's 7-Day Assignment Pass is $7.99 once for 7 days of unlimited use.
Sources & Methodology
- →Undetectable AI: pricing (undetectable.ai/pricing)
- →Undetectable AI: terms of service (undetectable.ai/terms)
- →QuillBot: AI humanizer (quillbot.com)
- →QuillBot: Premium (quillbot.com/premium)
- →WriteHuman: pricing (writehuman.ai/pricing)
- →Grammarly: AI humanizer (grammarly.com)
- →Grammarly: plans (grammarly.com/plans)
- →GPTHuman: pricing (gpthuman.ai/pricing)
- →Phrasly: pricing and guarantee (phrasly.ai/pricing)
Pricing and features verified October 2026. Tools change frequently; we refresh this page periodically to maintain accuracy.
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