What the AI score means
A trained classifier reads the whole document and returns a score from 0 to 100. Higher means stronger evidence of machine writing on a balanced benchmark of human and AI texts. A middle result is marked uncertain. The score describes the document; it is not the share of AI-written words.
Why the text is highlighted
A second review quotes passages with explicit AI-writing patterns: stock phrasing, template contrasts, claims without specifics, repeated structure and more, each with an explanation. Literal stock phrases are added from a fixed list. The Watermark-free AI Humanizer can then create a new version for comparison.
From detection to a fix
Select Humanize and remove watermark under the result. The Watermark-free AI Humanizer creates a new version, compares it with your source and shows the AI score before and after.
The RAID benchmark and a practical detector evaluation describe why accuracy does not transfer automatically between writing settings. Researchers also found false positives in non-native English writing.
Questions about the AI Detector
How accurate is the AI detector?
On the final test of 2,000 new inputs it flagged 92.2% of machine-written English texts with 3.4% of human texts flagged. Results differ by genre and by generator; the methodology page publishes the full report. Treat the score as strong evidence, not proof.
Is this an AI detector or a watermark detector?
An AI detector: it estimates how much the writing resembles machine output. Watermarks are a separate hidden layer; the AI Watermark Detector page compares an original with a rewrite for that.
How much text do I need?
Use at least 80 words of prose, within your account character limit. English has the fullest coverage. Shorter input receives highlights but no score.
Can it flag human writing?
Yes, about 3 to 4 human texts in 100 on the benchmark, more often for very formal or templated writing. The highlights show what triggered it; the Humanizer can rewrite those passages.
Do the highlighted passages set the score?
No. The classifier sets the score for the whole document. The highlights separately explain which patterns stand out, and their own percentage counts words inside highlighted passages.
Does an AI check share my other tools quota?
No purchased rewrite is used. AI checks are free and limited to 100 successful checks per person each UTC day. Rewrites have a separate trial and purchased balance.
Use the same account through the MCP server or API, or browse all tools.
Updated 2026-09-13.