Turnitin AI checker, free: what actually exists
There is no free student version, and the sites promising one are not running Turnitin. Here is what the free options really are.
This is one of the most searched things in the whole subject, and the honest answer is short: Turnitin is licensed to institutions, not to individuals. Access runs through your institution's account, the AI indicator is generated automatically on submission, and the report appears where staff can see it.
Some institutions enable a draft submission area. Whether the AI indicator shows there is a per-institution setting, and in most configurations it does not.
About the sites offering "free Turnitin checks"
A site that is not your institution is not running Turnitin. Whatever it is running, the result it hands back is that tool's number, not the one your institution will see.
Worth knowing what you are trading for it as well. Pasting an unsubmitted essay into an unknown service means handing unpublished work to a third party whose retention and training policy you have not read. See what happens to text you paste.
What a second detector can actually tell you
Not a prediction of Turnitin's number. Different tool, different threshold, different segmentation, so the figures will not match, and any site promising a match is guessing.
What it tells you is the shape: which paragraphs in your document carry the properties every detector reads as machine-written. That part is stable across tools, because they are all reading the same underlying regularity. A section that comes back flat in one comes back flat in the other.
That is the useful thing, because it is also the actionable thing.
The number to compare any free tool on
How often it is wrong about genuine human writing, since that is the error that arrives attached to somebody's work.
Turnitin publishes 4%. Ours is 0.4%, which is 99.6% specificity, measured across 15,900 documents of real academic writing.
Most free tools advertise a blended accuracy figure instead, which can be raised by getting better at either error and tells you nothing about your own risk.
How to run a free check so the result means something
The whole document, not an extract. Length is the single largest factor in reliability. Turnitin's own figures: 4% wrong on sentences against under 1% on documents. A word cap that forces you to check an essay in fragments degrades the answer. See why detectors are unreliable on short text.
Per paragraph, not one percentage. In most essays two or three paragraphs carry the whole signal and the rest are fine. A document average hides which.
On the final draft. Editing raises the score, because smoothing removes variation, so a check on an earlier version understates what the submitted one will do. See why good writing gets flagged more.
More than once. Fix the highest paragraph, run it again. That loop needs a tool with no cap and no per-check limit.
Ours is free and unlimited with no account, takes .pdf, .docx and .tex, has no word cap, scores every paragraph separately, and never stores your text. There is nothing to sign up for and no institution to go through.