Free ChatGPT detector • No sign-up • Up to 500 words
Was this written by ChatGPT, Claude, or Gemini?
Free AI writing detector that scores any text across three independent signals — AI tell phrases, sentence rhythm, and an LLM judgement. No login, no upload, no data retention. And we're honest about what free AI detectors can and can't tell you.
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How it works
Three independent signals
We combine three different methods and show you each one separately, so you can see which signals are firing and decide for yourself.
AI tell phrases
We scan for phrases that AI models overuse — "It's important to note," "leverage," "delve into," "fast, efficient, and reliable," and similar corporate-filler patterns. More hits = higher AI score.
Sentence rhythm
Human writing varies sentence length dramatically — short, long, fragments, complex. AI tends toward uniform medium-length sentences. We score the variance.
LLM judgement
We send the text to a separate AI and ask it to evaluate the writing style. It returns a score and a short explanation. This is the qualitative signal.
More free tools
AI Humanizer
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Free rewrite that removes the AI tells we just flagged. Preserves meaning exactly.
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Per-request + monthly cost across 12 frontier models, including prompt-caching discounts.
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When the detector is unreliable
FAQ
Common questions about our ChatGPT detector
Can this detect ChatGPT?
Yes. Our AI text detector is built to spot writing from ChatGPT (GPT-4, GPT-5), Claude (Sonnet, Opus 4.7, Opus 4.8), Gemini (3.5 Pro, Flash), Grok, and most other major LLMs. The three-signal approach — AI tell phrases, sentence rhythm, and an LLM judgement — catches the patterns these models share.
How is this different from GPTZero or Copyleaks?
Three differences. (1) We show three signals separately instead of one black-box number, so you can see which patterns are firing. (2) We're upfront about accuracy — most free AI detectors are 50–65% reliable per published research. (3) No sign-up, no upload, no data retention.
Does it detect Claude or Gemini text?
Yes. The detector is model-agnostic — it looks for patterns common to modern LLMs (uniform sentence rhythm, AI-typical phrases like "It's important to note" and "leverage", tricolons like "fast, efficient, and reliable"). Claude, Gemini, GPT-5, Grok, and DeepSeek all show these signals.
How accurate are free AI detectors in 2026?
Free AI detectors are roughly 50–65% accurate per published research, especially weak on short text, edited AI, technical writing, non-native English, translated text, and humanized AI output. Treat any detector result — including ours — as a hint, not a verdict.
Is this a ChatGPT detector or a general AI detector?
Both. ChatGPT is the most common LLM, so spotting ChatGPT writing is the primary use case. But the same signals that catch ChatGPT also catch Claude, Gemini, Grok, and other LLMs — so it works as a general AI writing detector.
What's the minimum text length for accurate results?
30 words minimum, 100+ words recommended. Short text doesn't have enough data for the rhythm and phrase signals to be meaningful. Anything under 100 words is mostly guesswork — for our detector and for tools like GPTZero, Copyleaks, and Originality.ai.
Can AI detectors be fooled by humanized text?
Yes. A good AI humanizer rewrites text to break the patterns detectors look for — uniform sentence length, AI tells, tricolons. Our companion humanizer at /ai-humanizer does exactly this. If detection accuracy matters to you, don't rely on it alone.