Head to head · QuillBot
QuillBot vs Undetected AI: a paraphraser and a humanizer are not the same tool
The short answer
QuillBot and Undetected AI solve different problems. QuillBot is a paraphrasing and grammar suite: it reword sentences, fixes writing, and now bundles a humanize feature, all for $8.33 a month billed yearly, verified August 10, 2026. Undetected.ai does one job, rewriting AI text so it reads like a person wrote it, and shows our own AI-pattern score for the draft and the rewrite with the reasons behind both. If you want an all-round writing assistant, QuillBot is excellent value. If the actual job is beating detection, a paraphraser is the wrong tool, and independent tests keep showing QuillBot-style paraphrased text still getting flagged.
Last updated July 2026 · Pricing read off each vendor's own page
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.
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Meaning kept · Your own text rewritten · Saved to your history, delete any time
QuillBot is one of the most popular writing tools on the internet, and deservedly so. It paraphrases, checks grammar, summarizes, generates citations, and, more recently, offers a humanize feature inside the same subscription. For general writing help it is hard to beat at the price.
The confusion starts when people reach for QuillBot to beat an AI detector. Paraphrasing and humanizing sound like the same thing, but they change different properties of your text, and detectors measure the properties paraphrasing leaves untouched. This page compares the two tools honestly: what each is built for, the pricing as verified on August 10, 2026, and which one actually clears a detector.
Verified pricing
QuillBot vs Undetected.ai pricing
QuillBot prices read off quillbot.com on August 10, 2026, when the $8.33 yearly rate was confirmed unchanged. QuillBot bills the whole suite as one subscription rather than a per-word humanizer plan, so the tiers below are not a like-for-like word-pool comparison. Check their page for the latest.
| Plan level | Undetected.ai | QuillBot |
|---|---|---|
| Entry plan | Starter: 15,000 humanized words/mo at $9/mo billed yearly ($12 monthly) | Premium: $8.33/mo billed yearly ($99.95/year); $19.95 month-to-month |
| What you get | A focused humanizer with our own AI-pattern score before and after, and its reasons | Full writing suite: paraphraser, grammar, summarizer, citations, plus a humanize feature |
| Higher volume | Pro 80,000 words/mo ($19); Scale 250,000 words/mo ($39/mo billed yearly) | One flat Premium price; a Team plan for shared billing (contact QuillBot) |
| Free usage | Free account: 3 runs/day, 9,000 words/mo; the on-page demo runs twice a day with no account | Free plan: 125 words per paraphrase, limited humanize, 2 of 9 modes |
Prices change and promos expire. Always confirm on each vendor's pricing page before buying.
Side by side
What each tool actually does
A fair look at where each one wins. Both are capable humanizers; the fit depends on your volume and workflow.
| What matters | Undetected.ai | QuillBot |
|---|---|---|
| What the tool is built to do | Rewrite AI text so it reads like a person wrote it | Reword and improve writing; humanizing is a newer add-on feature |
| What the product is built to change | The structural properties classifiers read: sentence-length variation, predictability, template phrasing. No claim about any named detector | Paraphrasing preserves the structure detectors measure; results vary |
| What you see after the rewrite | Our AI-pattern score before and after, with the reasons behind it | A human-score reading from QuillBot's own in-house detector |
| Long documents | Up to 1,500 words a run, rewritten as one piece rather than sentence by sentence | Paraphrase works sentence by sentence; long text is fine but stays structurally similar |
| Everyday writing help | Not the job; this is a humanizer only | Genuinely strong: grammar, tone, summaries, citations in one place |
| Best suited for | People whose specific goal is clearing AI detection | Writers who want an all-round assistant and treat humanizing as a bonus |
Paraphrasing and humanizing change different things
A paraphraser swaps words and reshuffles clauses while keeping the meaning. "The results demonstrate a clear improvement" becomes "the findings show a distinct enhancement." Different vocabulary, same sentence length, same clause order, same rhythm.
AI detectors do not keep a list of banned words. They measure how predictable your text is and how much your sentence structure varies. Synonym substitution barely moves either number, which is why detectors flag paraphrased AI text so often. A humanizer built for the job changes the structural properties detectors actually read: the sentence-length variation, the rhythm, the predictability. That is a different operation from swapping in a thesaurus, and it is the operation that clears a scan.
Does QuillBot bypass AI detection?
Not reliably. QuillBot\'s core paraphraser preserves the structure detectors measure, so paraphrased AI text frequently still scores as machine-written on GPTZero, Originality.ai, and Turnitin, which explicitly markets a paraphrase-detection signal. QuillBot has added a dedicated humanize feature that performs better than raw paraphrasing, but the tool does not center its product on clearing external detectors, and it does not show you what its rewrite changed.
There is also a conflict worth naming: QuillBot sells its own AI detector. A company that scores text for AI is a fine writing assistant, but it is not structured around the single goal of getting your text past the detectors a teacher, editor, or client is most likely to run.
Where QuillBot is genuinely the better buy
For most writing tasks that are not about beating detection, QuillBot is excellent and, at $8.33 a month billed yearly, a lot of tool for the money. If you want one subscription that paraphrases, fixes grammar, summarizes long documents, and generates citations, QuillBot does all of it well, and its humanize feature is a reasonable bonus for light needs.
Undetected.ai does not compete on that breadth. It is a humanizer, full stop. The two are complements more than rivals: draft and polish in QuillBot, and when a piece has to clear a detector, run it through a tool built for exactly that. If your only reason to subscribe is passing detection, pay for the specialist rather than the suite.
The honest split
Who should pick which
Pick Undetected.ai if
- You want to know what changed in the rewrite, not just that something did
- You want a score that lists the reasons behind it, not one in-house human number
- You would rather a tool built for detection than a paraphrase feature inside a writing suite
Pick QuillBot if
- You want an all-round writing assistant: grammar, paraphrase, summarize, cite
- Beating detectors is a nice-to-have, not the reason you are paying
- One flat suite price for unlimited paraphrasing fits how you work
No tool wins every workload. Test both on your own text before committing to a year.
Good questions
QuillBot vs Undetected.ai, answered
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Further reading: Why writers switch from QuillBot · Can AI detectors detect paraphrasing? · What an AI paraphrasing tool can and cannot do
Try Undetected.ai on your own text
Paste your own text and read the rewrite next to the original, with our AI-pattern score measured on both before you copy.
Meaning kept · Your own text rewritten · Saved to your history, delete any time