Free AI Detector.
7 detectors. One click.
Paste your text and check it against GPTZero, Turnitin, Originality.ai, Copyleaks, ZeroGPT, Sapling, and Winston AI simultaneously. Free, unlimited, no signup. Know exactly what detectors see before anyone else does.
Paste the AI text. Get back something a human would actually write.
no signup. no card.
What we check and why.
Every AI detector uses a different approach. GPTZero focuses on perplexity and burstiness. Turnitin uses a proprietary sentence-level classifier trained on millions of student submissions. Originality.ai runs aggressive pattern matching tuned for content marketing. Copyleaks uses cross-model fingerprinting. ZeroGPT relies on sentence boundary analysis. Sapling combines multiple signals. Winston AI focuses on vocabulary distribution.
That's why checking one detector isn't enough. Text that passes GPTZero might fail Originality. Text that passes Turnitin might fail Copyleaks. Each detector has blind spots and strengths. Checking all seven gives you the complete picture.
HumanGPT's detector analyzes your text against the known detection patterns of each tool. We measure perplexity (how predictable each word is), burstiness (sentence length variance), vocabulary distribution, structural patterns, and model-specific tells. Then we estimate how each detector would score your text.
The result is a per-detector breakdown showing estimated AI probability for each of the seven detectors, plus overall perplexity and burstiness scores. If any detector shows a high score, you know exactly where the risk is.
The 7 detectors we check.
GPTZero
The academic standard. Used by universities and schools worldwide. Focuses on perplexity and burstiness analysis with sentence-level highlighting.
Turnitin
Built into university LMS platforms. Checks every submission automatically. Uses a proprietary classifier trained on student writing vs AI output.
Originality.ai
The content marketing standard. Used by agencies, publishers, and freelance clients. Most aggressive detection with the lowest false positive tolerance.
Copyleaks
Enterprise-grade detection with cross-model fingerprinting. Catches text from ChatGPT, Claude, Gemini, and Perplexity with model-specific classifiers.
ZeroGPT
Free, widely used detector with sentence boundary analysis. Popular with individual users and small publishers for quick AI checks.
Sapling
Multi-signal detector combining perplexity, vocabulary, and structural analysis. Used by content teams and editorial workflows.
Winston AI
Vocabulary distribution focused detector. Strong at catching paraphrased AI content that simpler detectors miss.
Understanding your scores.
0-20% AI probability: Safe. All major detectors classify this as human-written. You can submit or publish with confidence.
20-50% AI probability: Borderline. Some detectors might flag sections for review. Consider humanizing flagged portions with HumanGPT on Medium mode.
50-80% AI probability: High risk. Most detectors will flag this as likely AI-generated. Needs full humanization on Medium or Heavy mode.
80-100% AI probability: Almost certainly flagged. Raw AI output from ChatGPT, Claude, or Gemini typically scores in this range. Heavy humanization recommended.
Perplexity score: Human writing typically shows perplexity between 60 and 100+. AI text sits between 15 and 30. After HumanGPT humanization, perplexity rises to 55-80, matching human patterns.
Burstiness score: Human writing has high sentence-length variance (15-30+). AI text is flat (under 5). HumanGPT injects natural burstiness to bring variance into the human range.
The check-humanize-check workflow.
The most reliable approach is a three-step loop: check, humanize, check again.
Step 1: Check. Paste your AI-generated text into the detector. See which detectors flag it and how high the scores are. This tells you how much humanization you need.
Step 2: Humanize. Run the text through HumanGPT. If scores were 80%+, use Medium or Heavy mode. If scores were 50-80%, Medium is usually sufficient. If scores were 20-50%, Light mode might be enough.
Step 3: Check again. Paste the humanized text back into the detector. All seven detectors should now show under 20%. If any detector still shows above 20%, bump up the humanization mode and repeat.
This loop takes under 60 seconds total. Check, humanize, verify. Then you're safe to submit or publish.
AI Detector FAQ.
Everything you need to know.
HumanGPT's detector analyzes your text against the detection patterns used by all seven major AI detectors. It evaluates perplexity (word predictability), burstiness (sentence length variance), vocabulary patterns, and structural tells. You get a per-detector score estimate plus overall AI probability.
Yes. The detector is free with no word limit and no signup. Paste your text, click check, get results. The humanizer has a 200 words/day free limit, but the detector itself is unlimited.
GPTZero, Turnitin, Originality.ai, Copyleaks, ZeroGPT, Sapling, and Winston AI. Seven detectors in one click. Each has different detection methods, so checking all seven gives you the most complete picture.
Yes. That's one of the most common use cases. Paste your essay, check the Turnitin score. If it's above 20%, humanize it with HumanGPT and check again. Repeat until all seven detectors show human.
The detector focuses on whether text is AI-generated, not which specific model wrote it. ChatGPT, Claude, Gemini, and Perplexity all have slightly different detection profiles, but the core question is the same: will a detector flag this?
Our estimates correlate at 92%+ with actual detector results based on our weekly testing. For critical submissions (academic papers, client deliverables), we recommend running the actual detector as a final check. Our tool gives you a reliable preview.
Perplexity measures how predictable each word is given the context. AI text has low perplexity (15-30). Human text has higher perplexity (60-100+). Burstiness measures sentence length variance. AI text has flat burstiness (variance under 5). Human text is bursty (variance 15-30+). Both metrics help distinguish AI from human writing.
Yes. The detector works across 30+ languages. AI detection patterns (perplexity, burstiness, structural uniformity) are language-agnostic, so the analysis applies regardless of language.
One text box. Seven detectors. Zero signup. Know exactly what detectors see before submitting your work.
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