Turnitin AI Detection vs Similarity Score

Turnitin AI detection and Turnitin similarity score measure different things. Students often confuse them, but they are used for different types of academic risk.

Similarity score

The similarity score checks whether your paper overlaps with existing sources, student papers, websites, or publications. A high similarity score may indicate plagiarism, missing citations, or too much copied wording.

AI detection score

The AI detection score estimates whether the writing style looks AI-generated. It does not measure copied text. A paper can have a low similarity score and still have a high AI score.

Why both matter

Before submission, students should check both indicators. A paper may need citation fixes if the similarity score is high. It may need rewriting or humanizing if the AI score is high.

Quick example

If your essay has 5% similarity but 70% AI, the issue is not copied sources. The issue is that Turnitin thinks the writing style looks AI-generated.