Writing
Free AI Detector — Estimate If Text Was AI-Generated
Paste any text and get a likelihood score, plus the linguistic signals behind it — perplexity, burstiness, and generic phrasing.
What is AI Detector?
Cobain AI's AI Detector estimates how likely a piece of text was written by AI rather than a person. Paste a paragraph or a full article and you get a probability score along with the linguistic signals behind it — how predictable the wording is (perplexity), how much the sentence rhythm varies (burstiness), and whether the phrasing leans generic.
Key features
Likelihood score, not a verdict
Get a clear probability estimate instead of a misleading yes-or-no claim about who wrote the text.
Shows the signals
See the cues behind the score — perplexity, burstiness, and generic phrasing — so you understand the reasoning.
Works on long text
Check a single paragraph or a full article in one pass to spot which sections feel machine-written.
Built for honesty
The result is framed as an estimate, with reminders that no detector can prove authorship for certain.
Free to try
Run your first checks for free with a Cobain AI account, with paid options for higher volume.
How it works
- 1
Paste your text
Add the paragraph, essay, or article you want to check.
- 2
Run the detector
The AI analyzes the wording and scores how likely it was machine-generated.
- 3
Read the signals
Review the likelihood score and the signals behind it before drawing any conclusion.
Perfect for
Frequently asked questions
Is the AI detector free?
Yes. You can start checking text for free with a Cobain AI account, with paid options for higher volume.
Can it prove that text was written by AI?
No. The result is a probabilistic estimate, not proof. No detector can prove AI authorship with certainty — treat the score as one signal among many, never as definitive evidence.
Should I use it to fail a student or discipline someone?
No. Because the result is only an estimate and can be wrong in both directions, you should never use it as the sole basis for academic or disciplinary decisions. Always combine it with human judgment and context.
What do the signals mean?
Perplexity reflects how predictable the wording is, burstiness reflects how much sentence rhythm varies, and generic phrasing flags wording that tends to appear in machine-generated text.
Why might the score be wrong?
Polished human writing can look machine-like, and edited AI text can look human. Short samples are especially unreliable, so always read the result with that in mind.
Ready to try it?
Create your free account and start in seconds.
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