Turnitin AI writing detection
The detector most students meet. It reports a percentage of a submission that it judges likely AI-written. AI bypasser detection, announced August 27, 2025, flags text that humanizer tools may have rewritten and counts it toward the AI-generated total. Bypasser detection is trained and tested for English only.
What it is
Turnitin's AI indicator is a classifier, not a watermark reader. It scores sentences on how likely they are to have been produced by a model and reports an overall percentage. The August 2025 bypasser detection added a second signal trained on the output of humanizer tools, and that text now counts toward the AI-generated total. Turnitin's own guidance says the percentage should prompt a conversation, that short submissions are unreliable, and that the model is trained and tested for English, with Spanish and Japanese detectors lacking the paraphrase and bypasser features. The score is only visible to instructors on licensed accounts; students generally cannot see it before submitting.
Known limits
Several universities have switched the AI indicator off over false-positive concerns. Turnitin's own guide says a score should start a conversation, not decide an outcome.
When to use this entry
Use this entry when a question is about a Turnitin score, bypasser detection, or how an institution should treat the number.
Questions
Can students check their work in Turnitin before submitting?
Usually not. The AI writing report is an instructor-side feature on licensed accounts.
What does the Turnitin AI percentage mean?
The share of the submission that the model judges likely AI-written, including text it believes was humanized. Turnitin says it is an indicator, not a verdict.
Does Turnitin detect text that was run through a humanizer?
Turnitin says its bypasser detection, launched August 27, 2025, flags text altered by humanizer tools, for English submissions.