Free ChatGPT AI checker
ChatGPT Detector: find out if text was written by AI
Paste any text below and get a sentence-by-sentence verdict in seconds. 95.2% accuracy and 3.1% false positives in our April 2026 benchmark (500 texts) — trained on ChatGPT, GPT-5, and paraphrased GPT output. No sign-up needed for your first scan.
95.2%
accuracy, April 2026 benchmark
3.1%
false positive rate
<10s
to a full result
500
texts in the benchmark
Why this ChatGPT checker beats a gut feeling
"It sounds like ChatGPT" is not evidence. A trained detector with published accuracy numbers is.
Built for GPT models specifically
GPT-4o text is the strongest model class in our April 2026 benchmark (500 texts), where the engine scored 95.2% overall. GPT-4o, GPT-4.1, GPT-5, and o-series reasoning output are all in the training data.
Sentence-level highlighting
Instead of one opaque score, every sentence is highlighted by AI likelihood — so you can see exactly which passages look ChatGPT-written and which read human.
Low false positives
A 3.1% false positive rate across demographics, including ESL writers — the group other ChatGPT detectors flag most often. Human writing should not fail an AI check.
Catches paraphrased ChatGPT
Text run through QuillBot or "humanizer" tools keeps statistical traces of its GPT origin. Our detector is trained on paraphrased and lightly-edited ChatGPT output, not just raw generations.
Essays, articles, emails, code comments
Works on any English prose from ~80 words up. Teachers check essays, editors check submissions, recruiters check cover letters — same engine, same score.
Free to start, no sign-up
Your first scan needs no account. Free accounts get daily credits; Pro removes the limits at $9.99/month. No institutional contract required.
How ChatGPT detection actually works
ChatGPT does not sign its output — there is no hidden watermark to look up. What it does leave is a statistical fingerprint: language models choose words with measurably different probability patterns than people do. Human writing is bursty — it mixes short punchy sentences with long winding ones and makes surprising word choices. GPT output is smooth, evenly weighted, and consistently "likely."
Our detector is a classifier trained on a large corpus of paired human and AI samples — raw ChatGPT generations, paraphrased GPT text, and genuine human writing across essay, article, and email registers. It scores each sentence independently, then aggregates into a document-level verdict. That is why you get highlighting instead of a bare percentage: mixed documents (human draft, AI-polished paragraphs) are the norm, not the exception.
We published accuracy numbers for our engine and nine competitors on a fixed 500-text corpus in April 2026 — see our April 2026 benchmark for per-model results, false positive rates and methodology.
ChatGPT detector FAQ
How accurate is this ChatGPT detector?
In our April 2026 benchmark of 500 texts across 5 AI models, our detector scored 95.2% accuracy with a 3.1% false positive rate, and GPT-4o text was its strongest model class. You can inspect the full methodology and per-model numbers on our accuracy benchmark page.
Can it detect GPT-5 and the newest ChatGPT models?
Yes. The detection model is retrained continuously as new OpenAI models ship, and our benchmark tracks month-over-month accuracy so regressions are visible publicly. New model output typically scores slightly lower for the first weeks after a release, then recovers as training data accumulates.
Does ChatGPT leave a watermark I can check instead?
No. OpenAI has researched statistical watermarking but has not shipped a public, checkable watermark in ChatGPT text. There is no official tool that verifies text came from ChatGPT — statistical detection like ours is currently the only practical way to check.
Will it flag human writing as ChatGPT?
Our false positive rate is 3.1% — the lowest in our benchmark cohort. No detector is perfect, which is why we show sentence-level highlighting instead of a single verdict: a human-written text with one AI-flagged sentence reads very differently from a fully-flagged one. Treat any detector score as evidence, not proof.
Can it detect ChatGPT text that was paraphrased or humanized?
Usually, yes. Paraphrasing tools change surface wording but preserve much of the underlying statistical structure detectors key on. Heavily hand-edited text is genuinely harder — at some point edited AI text becomes human writing. The sentence highlighting shows you which parts still carry GPT patterns.
Is this ChatGPT detector really free?
Yes — your first scan requires no account, and free accounts receive daily scan credits. Pro ($9.99/month) removes limits and adds batch scanning. There are no institutional contracts; individual teachers, editors, and students can sign up directly.
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