Direct answer
Direct Answer - No. Grammarly's AI detector and Turnitin's AI writing detection are different tools built on different models, for different audiences, and they produce different kinds of scores [1]. Turnitin's AI writing indicator is embedded in the institutional Similarity Report and is visible only to instructors and administrators, whereas Grammarly is a consumer-facing checker that returns a simple likelihood percentage [1]. Because the two detectors are calibrated differently, a "human" result from Grammarly does not guarantee a low Turnitin AI score — only an actual Turnitin report tells you what your instructor will see [1].
How Do Grammarly and Turnitin AI Detectors Differ in How They Work?
Turnitin's detector is built into the academic submission workflow. The AI Writing Report takes the qualifying prose in a document and shows an overall percentage that Turnitin's model predicts could be AI-generated, split into two categories: text that is AI-generated only, and text that was AI-generated and then AI-paraphrased [2]. That AI percentage is different from and independent of the Similarity score, and its highlights do not appear in the Similarity Report [2]. Grammarly, by contrast, runs a standalone check on whatever text you give it and returns one verdict — there is no submission workflow, no category breakdown, and no similarity matching.
The score displays are not comparable either. Turnitin deliberately suppresses scores between 0 and 20 percent, showing an asterisk (*%) instead of a number, because sub-20 results carry a higher incidence of false positives [2]. Turnitin also only processes long-form prose in supported formats — at least 300 words, in.docx,.pdf,.txt, or.rtf, and in English, Spanish, or Japanese [2]. Grammarly will score short paragraphs, bullet points, and mixed text, which is exactly the kind of input Turnitin's model is not designed to judge.
The purpose is the real difference. Turnitin frames its detection as data for educators to review within their academic policies, not as a verdict on misconduct [2]. Grammarly's detector is a productivity feature for everyday writers. Both answer "was this written by AI?" — but they measure different writing, with different models, for different decisions.
Can a Grammarly AI Score Predict Your Turnitin AI Score?
No. Turnitin's AI writing detection is one component of an institutional integrity suite built with educators for educators, and it is calibrated on academic writing to keep the false-positive rate under 1 percent for documents containing more than 20 percent AI-generated content [3]. Grammarly's detector is trained and tuned for a general audience, so its percentage reflects a completely different model [3].
Turnitin is explicit that its AI writing detection does not make a determination of misconduct and should be treated as an indicator for informed decision-making, not a definitive score [3]. Detection is probabilistic: two detectors frequently disagree on the same passage, and neither can be used to forecast the other. A "likely human" verdict from Grammarly only tells you what Grammarly's model concluded — it says nothing about the score Turnitin's model will produce.
The asymmetry goes further. Turnitin reports scores below 20 percent as an asterisk rather than a number, precisely because low scores are less reliable [2]. And because students generally cannot preview their official Turnitin result on their own, a Grammarly "pass" can easily create false confidence before the report that actually matters [4].
How Can You Get a Reliable Turnitin AI Score Before Submitting?
As a student, you cannot self-check a paper inside Turnitin without uploading it to an official assignment created by your instructor, unless your institution has enabled Turnitin Draft Coach [4]. If Draft Coach is unavailable, your only option is resubmission-based checking, which is tightly limited: classic assignments generate a report immediately for the first three attempts and then impose a 24-hour wait, while new assignments allow up to three resubmissions per day [4].
If your instructor has disabled resubmissions, your first upload is final, and you have no official way to check your draft beforehand [4]. That is why consumer detectors like Grammarly feel convenient — but convenience is exactly the risk, because a third-party score cannot reproduce the official report that your instructor actually opens [3].
The reliable path is to run your draft through the genuine Turnitin AI detection engine before submission day. That gives you the real indicator, the real percentage (or *%), and the sentence-level highlights — so you can revise and resubmit while you still can, instead of discovering the number after it counts.
Because Turnitin doesn't let students generate their own AI report, the only way to know your real number before submission day is to check with the same engine your instructor uses. turnitin0 does exactly that: upload your.docx,.pdf, or.txt and get the genuine Turnitin AI writing report — the same indicator, percentage (or *%), and sentence-level highlights your professor will see — delivered in minutes, backed by more than 100,000 real reports delivered to students worldwide.
※ Turnitin0.com - Actual Turnitin AI Report Cover, Score, Flag And Similarity Summary
FAQ
1. Is Grammarly's AI detector the same as Turnitin's AI detector?
No. They are different products with different models, score types, and audiences [1]. Grammarly is a consumer checker, while Turnitin's detection is an instructor-facing indicator embedded in the institutional Similarity Report [1].
2. If Grammarly says my writing is human, will Turnitin show 0%?
Not necessarily. Detectors are probabilistic and frequently disagree on the same text. Turnitin even displays scores below 20% as an asterisk (*%) rather than a number because low scores are less reliable [2].
3. Can I see my Turnitin AI score before submitting?
Only if your institution has enabled Turnitin Draft Coach, or if your instructor's assignment allows resubmissions [4]. Otherwise you have no official way to preview your own report [4].
4. Why does Turnitin show *% instead of a number?
Turnitin suppresses AI scores between 0 and 20% to reduce the risk of misinterpreting unreliable low-end results; scores in that range are displayed as an asterisk [2].
5. Is the AI percentage the same as the Similarity score?
No. Turnitin's AI writing detection percentage is different from and independent of the Similarity score, and the two measure entirely different things [2].