99.3% AI was ZeroGPT’s verdict on Lewis Carroll. The human control scored above every generated passage I submitted. That’s the result I’d check before trusting a detector’s confident label.
What I could actually compare
I reused six unchanged English passages: generated writing in different formats, a Carroll excerpt, and an AI-edited version of that excerpt. Some samples were related, so I wouldn’t treat this as a broad accuracy study.
I counted completed checks, not blocked submissions or leftover scores. I also kept access problems separate from detection failures. A signup screen tells me nothing about whether a detector works.
Where the results stopped adding up
ZeroGPT caught the generated texts but failed the human control. NoteGPT also gave Carroll its strongest AI score. Matching scores don’t establish shared technology.
QuillBot accepted all four generated passages as human. Scribbr missed the essay too; its visible QuillBot branding kept me from counting it as an independent vote.
SciSpace and Proofademic’s public demo also missed the essay. Surfer accepted both generated passages it checked. I couldn’t establish why.
My full run with Clever AI Detector needed neither payment nor signup. It separated the generated passages from Carroll, but accepted the edited excerpt as human. I couldn’t verify advertised unlimited use, and sentence-level explanations sometimes conflicted with the headline.
Pangram correctly classified its completed generated and human checks, though credits ran out. It also accepted the edited excerpt as human. AI or Not got its completed checks right; mixed writing wasn’t tested there.
Sapling correctly handled the complete story and Carroll, but truncated the essay. GPTZero caught its generated inputs before signup intervened; changing text left an old score onscreen, not a fresh result.
Grammarly and Quetext caught the essay, then blocked further guest attempts. Neither gave me a human-control result.
Decopy requested login; Smodin hid its headline values. I couldn’t assess either.
AI Detector Pro and Winston AI required registration. I stopped before scanning, leaving their advertised allowances unverified.
Copyleaks’ applicable-use terms stopped my review, not a failed scan. Turnitin needed institutional access I didn’t have.
Hive’s inspected demo handled media; I didn’t configure its text options. ContentDetector.AI redirected to a Moxby extension I didn’t install.
Humanly’s listing offered a free download with in-app purchases. I verified neither scanning allowance nor detection.
A score still needs its label
I wouldn’t read confidence, probability, and estimated AI share as interchangeable. Originality.ai correctly classified its completed generated and human samples, but guest access ended before broader testing. I selected its 15% AI Allowance setting; its confidence described the threshold-based verdict, not the proportion of generated words.