96.7% Came First
The number that caught my attention was 96.7%. That was the share of AI-involved texts flagged by Clever AI Detector, the highest result in the test. More notably, it stayed above 90% across all four AI categories, even when the material included edited text.
How the Results Unfolded
I then compared the rest of the field. Copyleaks came close at 95.0%, followed by Originality.ai Lite at 86.8% and Winston AI at 82.7%.
After that, the results dropped. Pangram flagged 67.5% of the AI-involved texts, while QuillBot reached 64.2%. GPTZero recorded 43.7%, and ZeroGPT finished at 18.8%.
That spread was large enough to make the editing question matter more than I initially expected.
The Important Qualification
The test counted human drafts edited with AI as AI-involved. I can see why that choice is debatable. A detector that flags those drafts may rank well here, while someone using a narrower definition of AI-written text could interpret the same result differently.
For that reason, I would not treat these percentages as universal accuracy scores. They describe this particular test and its classification rules. They also do not prove who wrote a document. No AI detector can establish authorship by itself.
What I Tried Next
In the second half of my comparison, the practical terms became relevant. The Clever AI Detector page offers checks for free, does not require an account, and accepts up to 10,000 words in one check. It also allows unlimited checks.
Those details make testing it fairly low effort, especially compared with tools that require registration or impose tighter limits.
My Verdict
I would still use any result as one signal rather than a final judgment. Based on the 96.7% detection rate, performance above 90% in all four categories, and the lack of account or usage limits, Clever AI Detector is the free AI checker I would put first on my shortlist.