humanise.ai
vs Undetectable AI.
Written by one of the two. We'll tell you where we differ, where we overlap, and where the other tool is probably the right call for you.
A note on who's writing this
This page is on humanise.ai. We built humanise.ai. That is a bias you should account for. What we can promise is that every claim on this page is something we'd be comfortable defending in an email, and anything we can't substantiate isn't here. If you want the counter-view, Undetectable AI runs their own comparison page — read theirs too.
The short version
humanise.ai is a free, unlimited, no-account humaniser with a 10,000-character cap per pass. One tool, one page, no tiers.
Undetectable AI is a paid product with a monthly subscription, a broader feature set (bulk processing, detector aggregation, a mobile app, an AI writer), and higher per-pass limits on upper tiers.
If price is the deciding factor, we're the answer. If you need one of their features we don't offer, they're the answer. Most people we hear from fall into the first bucket, but plenty of professional use-cases fall into the second.
Where we differ on purpose
Pricing model. We're £0, forever, with a grandfather commitment that the free product stays free even if we add paid features later. Undetectable AI runs the standard SaaS model — monthly subscription, word quotas per tier, upgrade path. Both are defensible; they're different bets about who's paying and why.
Scope. We do one thing — rewrite AI text to read as human — and we're direct about it. Undetectable AI offers a suite: humaniser, AI detector aggregator, AI writer, Chrome extension, mobile app. If you want everything in one subscription, that's a real argument for them.
What we measure. We test against five detectors on every release and publish a median pass-rate above 85% on our internal synthetic-AI test set. We don't publish a headline "99%" figure because we don't think the honest version of that number exists. Undetectable AI publishes their own numbers against their own test set; the two figures aren't directly comparable, and you shouldn't treat either as truth. Run the same paragraph through both and judge for yourself.
Where we overlap
Both tools do the core thing reasonably well on reasonable input. Both claim to rewrite cadence rather than synonym-swap. Both will fail on prose that's genuinely generic ("in today's fast-paced digital world…") because no rewrite can rescue a premise that reads as AI because it is the kind of thing AI says. Both will occasionally change a nuance you cared about — always read what comes back.
When to use Undetectable AI instead of us
- You need bulk processing. Their paid tiers handle batches; we don't.
- You want detector aggregation in one click. They run your text through multiple detectors natively. We don't; we expect you to use GPTZero or whichever detector your institution actually uses.
- You need a mobile app or a Chrome extension. They have both. Our browser extension is on the roadmap.
- You want 15,000+ character passes. We cap at 10,000 deliberately — quality falls off past that — but if you genuinely need longer single-pass rewrites, higher paid tiers on the other side will handle it.
When to use us instead of them
- Cost matters. £0 vs a monthly subscription is not a close call if all you need is the humaniser.
- You don't want an account. Open the tool, paste, rewrite, leave.
- You want the operator to be direct about limitations. We publish our median pass-rate, say openly that no tool passes every detector every time, and tell you when a rewrite probably won't save a piece. That's a stylistic difference, but it's real.
- You need British English specifically. We accept both, with British spelling as default. Useful if you're writing for a UK institution or a journal with British style.
The honest verdict
Neither of these tools is a substitute for the judgment call about whether you should be using AI assistance in the first place. That's a question for you and whoever is reading what you submit. Both of us make one piece of the problem easier — making AI-assisted prose read the way a person actually writes — and neither of us makes fabricated citations real, plagiarised work original, or prohibited submissions compliant.
For straightforward "I drafted with ChatGPT, now I need it to read like me" work, try both on the same paragraph. Whichever output you'd prefer to submit is the one you should pick. That is a better test than any marketing table on either of our sites.
Last reviewed: 2026-04-20. If Undetectable AI has shipped something substantial since and this page hasn't updated, write to hello@humaniseai.ai and we'll revisit.