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Free AI Content Detector

Paste any text to see how AI-generated it reads — based on sentence variance, common AI phrasing, and repetition. Up to 500 words, free.

AI Content Detector

Estimates how likely text is AI-written

0/500

Press Ctrl + Enter to analyze

This is our own statistical heuristic (sentence-length variance, AI-signature phrases, word repetition) — not GPTZero, Originality.ai, Turnitin, or any trained AI-detection model. Treat it as a rough signal, not proof.

The short version

A transparent signal, not a black-box verdict

Most AI detectors are black boxes — you get a percentage with no explanation of how it was reached. This one shows its work. It looks at three measurable writing patterns, the same kind of signals researchers point to when they explain how AI text tends to differ from human writing, and shows you exactly which sentences tripped which signal.

It won't out-perform a trained detection model built on millions of labeled examples. What it will do is give you an instant, explainable, completely free read on your text — and tell you honestly when it isn't sure.

HUMANAI

The three signals we measure

No hidden model, no mystery score — just patterns you can verify yourself.

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Sentence-length variance

Human writing mixes short punches with longer, winding sentences. AI text tends toward a steady, even rhythm — we measure that "burstiness".

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AI-signature phrases

Stock phrases like "delve into" or "it is important to note" show up far more often in model output than in typical human writing.

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Word repetition

Lower lexical diversity — reusing the same words relative to text length — is another common AI fingerprint.

Us vs. commercial AI detectors

What you're actually getting

What matters
Paid detectors
This tool
How it decides
A trained ML model scores probability from labeled datasets
A transparent, rule-based heuristic you can read the logic of
Cost
Often paid / limited free checks
Free, unlimited within the word cap
Speed
A few seconds
Instant
Accuracy claim
Marketed as highly accurate
Honestly a rough signal, not proof

One honest note before you trust the score

No AI detector — free or paid — is 100% accurate. This one is upfront about being a heuristic: it flags patterns statistically associated with AI writing, not a verified fingerprint. Use it to sanity-check text, not to make high-stakes accusations about someone else's work.

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Frequently Asked Questions

We analyze three statistical signals in your text: sentence-length variance ("burstiness" — human writing tends to mix short and long sentences, AI writing tends toward uniform length), common AI-signature phrases (like "it is important to note" or "delve into"), and word repetition (lexical diversity). These combine into a 0-100 score.