TextSight ranks first for the Turnitin case, because it is the only tool compared here that shows you what changed in the output, re-scores its own output, and runs free on your own writing with no account. Undetectable.ai rewrites harder in a single pass; QuillBot has the most usable free tier. The table is below.
Now the caveat that should shape how you read any ranking on this phrase, ours included. No vendor can measure its own product against Turnitin. Turnitin does not expose its verdict for third-party tools, so nobody selling a humanizer has a Turnitin score to show you, and a ranking built on a bypass rate is built on an invented number. This comparison is therefore built on what you can verify: whether the tool shows you what it changed, whether it re-scores its own output, whether you can test it on your own writing before paying, and what happens to your citations. If you want the mechanics of what a rewrite does and does not do to a Turnitin check, that is a separate page. This one is about picking a tool.
Ranked by our own criteria, which are published. We rank ourselves first and disclose the conflict of interest rather than pretending the page is neutral.
| Tool | Shows what changed | Re-scores the rewrite | Free trial on your own text | Best fit if Turnitin is the concern |
|---|---|---|---|---|
| TextSight | Yes, changed wording highlighted | Yes, before and after | Yes, 3/day no account | You need to see what a rewrite did to your citations |
| Undetectable.ai | No diff | No | Gates behind payment | You want the heaviest single-pass rewrite and will clean up after it |
| StealthGPT | No diff | No | Small preview | Monthly spend is your binding constraint |
| WriteHuman | No diff | No | Gates behind payment | You want to rewrite inside Docs or Gmail without switching tabs |
| QuillBot | No AI diff | No | Yes | You already pay for it and want paraphrasing in the same place |
| HumanizeAI | No diff | No | Yes | You want a basic free pass and nothing more |
Comparison is on product structure, not on bypass performance, because no vendor including us can measure the latter against Turnitin. Our full ranking and the criteria behind it are on the main best-of page.
On the free column specifically: ours is the only one in the table you can run on your own writing with no account and no card, at 3 humanizations a day up to 260 words. QuillBot's free tier is the most generous in the category, though it paraphrases rather than targeting AI signal. StealthGPT and WriteHuman gate behind payment. If a free trial on your own essay is the deciding factor, that narrows it to two.
Each one is something you can confirm in ten minutes with a free tier and your own paragraph. A bypass rate is not. That is the whole argument for comparing this way.
Shows what changed matters most for coursework, because the risk in a rewrite isn't style, it's a claim moving. If a tool hands back prose with no diff, you can't tell whether a citation now supports something your source didn't say.
Re-scores the rewrite tells you whether the tool measures its own output or just asserts it worked. We score before and after with our own detector and label the reading as ours. That is a real signal about statistical properties, and it isn't a prediction of Turnitin.
Free trial on your own text separates products you can evaluate from products you take on faith. A fifty-character teaser isn't a trial.
The only Turnitin figures anyone can honestly cite, and in one common case they argue against buying a humanizer at all.
Turnitin publishes about 4% false positives across the full distribution, and under 1% at document level above its 20% reporting threshold. Weber-Wulff et al. (2023) measured 4% to 12% independently. Our Turnitin explainer works through those figures, the threshold guidance and the Vanderbilt decision in full.
What matters on this page is what the rate does to your choice. 4% across a 200-student cohort is roughly eight human-written papers flagged. If you are one of those eight, no tool in the table helps you, and the one that looks most appealing will hurt you most: a rewrite deletes the draft history that would have cleared you.
So the rate splits this page's readers into two groups needing opposite things. Drafted with AI, not yet submitted? Pick a tool, and pick on visibility. Wrote it yourself and got flagged? Keep your evidence and buy nothing.
Figures: Turnitin AI Writing Detection Accuracy Documentation (2024); Weber-Wulff et al. (2023).
This is the only case where picking a humanizer is the right question. Choose on whether you can see the changes, because a coursework rewrite that quietly alters a cited claim is a worse outcome than a flagged draft. Use the lightest setting, work paragraph by paragraph, and check every sentence carrying a reference.
Do not pick a humanizer. Rewriting replaces the sentences you would use to show the work is yours. Gather version history, drafts and notes, and bring the false-positive figures above into the conversation. If you write English as a second language, there's specific published research worth citing.
Undetectable.ai rewrites harder in a single pass than we do. That is a real difference and we're not going to pretend otherwise. The cost is choppier output, flattened voice and occasional meaning drift, with no diff to catch it. For a blog post that's a fair trade. For a thesis chapter it is not.
StealthGPT has the lowest paid entry price in the category and bundles an AI writer. You give up the diff and the re-score entirely. Current TextSight plans are on the pricing page.
It won't tell you which tool passes Turnitin, because that isn't knowable from where any of us sit. It won't print a bypass percentage. It won't use the word undetectable about our own product, and you should discount any competitor page that does, because the claim is about a system the vendor can't see and a target that retrains against exactly these techniques.
It also ranks our product first, which you should weigh accordingly. The honest reason is structural rather than performance-based: we are the only tool in the table that shows the diff, re-scores its own output, and lets you test it on your own writing without an account. You can disagree with the weighting and still use the table.
TextSight, on the criteria that can actually be verified: it is the only tool compared here that highlights what changed, re-scores its own output with its own detector, and runs free on your own writing without an account. We disclose that this is our own product. Undetectable.ai rewrites harder in one pass and QuillBot has the most usable free tier, so those are the honest alternatives depending on what you weight. What no vendor can tell you, us included, is which tool passes Turnitin: Turnitin does not expose its verdict to third-party products, so any ranking based on a bypass rate is based on a number the vendor invented.
No, and a guarantee is the clearest signal to walk away. Detectors retrain specifically against rewriting techniques, so a claim about performance against a moving target is marketing rather than a measurement. What a rewrite demonstrably does is change the statistical properties detectors read. Whether that is enough for a specific version of a specific detector on a specific document is not something anyone can promise you.
Turnitin's 2024 accuracy documentation states under 1% false positives at document level above its 20% reporting threshold, and about 4% across the full distribution. Weber-Wulff et al. (2023) independently measured 4% to 12%, with the higher end driven by short submissions and translated text. Turnitin also tells instructors not to act below 20% and to treat 20% to 50% as a conversation rather than proof.
None of them. A rewrite replaces the sentences you would use to prove the work is yours and overwrites the draft history that supports you. Collect process evidence instead: version history, earlier drafts, notes and outline. Then cite the published false-positive figures, because roughly 4% across a 200-student cohort is about eight human-written papers flagged, and you may be one of them.
It can, and this is the failure that matters most in coursework. The reference marker rarely moves but the claim around it can. If a rewrite softens a direct finding into a general observation, your citation now supports something the source did not say, and that is a citation error you introduced and cannot defend. This is the main reason to prefer a tool that shows you every change.
That depends on your institution, not on the tool. Editing your own draft is ordinary writing practice. Submitting model-generated work as unaided is a different act, and a rewrite changes the prose rather than the authorship. Where your policy permits AI-assisted drafting and asks you to disclose it, disclose it. No tool can grant permission your institution has not.
Take two paragraphs of your own writing, not a sample, and run them through each free tier. Then check three things: did a citation change what it claims, did a technical term get swapped, did a hedge disappear. If the answer is no to all three and the reading moved, that tool works on your writing. That ten-minute test is worth more than any ranking, including this one.
The mechanics, and why no bypass rate can be honestly quoted.
Read the explainer →The full six-tool ranking with the criteria and the weighting.
See the ranking →What to do instead if you wrote it and were flagged anyway.
See the evidence list →The citation check that matters before anything is submitted.
Read the method →Policy first, then the tool, including the three cases.
Read the guide →What our own score cannot tell you, published rather than buried.
See the limits →Score a paragraph, rewrite it, read exactly what changed. 3 scans a day at up to 1,000 words, no account. That tells you more about a tool than any ranking, this one included.