AI Detector

Free AI score checker

What percentage of your text is AI?

Paste any text and get an exact AI percentage in seconds — with sentence-level highlighting that shows which parts drive the score, so you know what to fix instead of guessing.

0–100%

exact score, not a verdict

95.2%

benchmark accuracy

3.1%

false positive rate

$0

no sign-up to start

99.9%+ accuracySentence-level reportThird-party verified
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Detection details

AI models detected
ChatGPTGPT-4oClaudeGeminiLlama 3MistralGrok
What we check
  • Perplexity
    How predictable each word is
  • Burstiness
    Variation in sentence length
  • N-gram patterns
    Repeated phrase signatures
  • Stylometric fingerprint
    Author-level writing traits
Privacy-first scanning
We don't store or train on your text. If you share a report, only the score and a short preview are saved.

How to read your AI percentage

The number alone is not the point — what matters is which band you land in and which sentences put you there.

0–15%Reads as human

Normal territory for original writing. Occasional flagged sentences are usually formal or templated phrasing — nothing to act on.

15–40%Mixed signals

Typical of AI-assisted drafts: human structure with AI-polished passages. Check the highlighted sentences — if AI tools touched them, rewrite in your own voice before submitting anywhere with an AI policy.

40–100%Reads as AI

Most of the document carries AI statistical patterns. Any serious detector (Turnitin, GPTZero, an editor's checker) will flag it. Treat this as a rewrite, not an edit.

Institution-specific thresholds (Turnitin's 20% flag, journal policies, workplace rules) are covered in our guide: What percentage of AI is acceptable?

Who checks AI percentages

Students before submission

Turnitin shows AI scores to instructors, not students. Pre-checking your essay means the number on their screen is never a surprise.

Writers proving originality

Freelancers attach a low AI score to deliverables as evidence of original work — increasingly requested by clients and editors.

Teachers and editors verifying

A percentage plus highlighted sentences is fair, explainable evidence — far better ground for a conversation than a bare accusation.

Teams enforcing AI policies

Content teams with "AI-assisted but human-finished" rules use score bands to define what ships and what gets another editing pass.

Anyone fixing a flagged draft

The check-edit-recheck loop: scan, rewrite the highlighted sentences, scan again. Watch the percentage drop as the text becomes yours.

The falsely accused

If your human writing was flagged elsewhere, an independent second opinion with sentence-level detail is your best evidence. See our guide for the full playbook.

AI percentage checker FAQ

How is the AI percentage calculated?

The detector scores every sentence independently for AI-typical statistical patterns — word-choice probability, sentence rhythm, and structural predictability — then aggregates sentence scores into a document-level percentage. A 30% score roughly means the passages carrying about a third of your text read as AI-generated, and the highlighting shows you exactly which ones.

What AI percentage is acceptable?

It depends on who is checking. Turnitin historically surfaces documents above roughly 20% AI to instructors; many editors and clients expect 0% for bylined work; some workplaces accept AI-assisted drafting entirely. Under 15% is generally indistinguishable from ordinary human writing. Our guide on acceptable AI percentages covers institution-specific thresholds in detail.

Why does my 100% human-written text show an AI percentage above zero?

Formal register, template structures (cover letters, lab reports, five-paragraph essays), and ESL phrasing all overlap with AI statistical patterns. A nonzero score on human writing is normal and not evidence of anything — what matters is whether whole paragraphs light up, not whether the number is exactly zero. Our false positive rate is 3.1%, the lowest in our public benchmark.

Will different checkers give me different percentages?

Yes — sometimes wildly different, because each tool has different training data and calibration. That is why we publish a monthly benchmark comparing ten detectors on identical samples. A stricter, well-calibrated checker (higher detection accuracy, lower false positives) gives you the most conservative — and therefore safest — number to act on.

Can I lower my AI percentage?

Rewrite the highlighted sentences in your own words: vary sentence length, use specific details only you would know, and break predictable structures. Paraphrasing tools usually do not help — they swap words but keep the statistical smoothness detectors key on. For AI-assisted drafts you are allowed to use, our humanizer gives a head start, but your own edits work best.

Is the AI percentage checker free?

Yes — your first scan needs no account, and free accounts get daily credits for check-edit-recheck loops. Pro ($9.99/month) removes limits and adds batch checking for editors and teachers processing many documents.

Related tools & guides

What % of AI Is Acceptable? Turnitin AI Checker Falsely Accused of AI? Accuracy Benchmark

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