humanize.beer's free AI detector scans any text and shows how likely it is AI-generated, using GPTZero. Paste at least a few sentences for a human-vs-AI score in seconds — no sign-up and no word limit. It works on English and other languages, and gives a probability, not proof.
How the AI detector works
Paste at least 25 words of English text and click Check for AI. We run the text through a GPTZero scan and show two numbers: the probability the text is human-written and the probability it is AI-generated, plus a plain-English verdict:
- Likely human-written — AI probability under 30%.
- Mixed — between 30% and 70%. Often a human draft edited with AI, or the other way round.
- Likely AI-generated — 70% or more.
If the text reads as AI, the Humanize this text button sends it straight to the AI humanizer.
What AI detectors measure
Detectors don't “recognise” ChatGPT. They estimate how predictable the text is to a language model (perplexity) and how much that predictability varies from sentence to sentence (burstiness). AI text tends to be uniformly predictable; human writing jumps around. Modern detectors like GPTZero also use classifiers trained on large sets of human and AI writing. Read the full explanation in how AI detectors work.
Read the score carefully
No AI detector is proof on its own. Things that commonly cause false positives:
- Writing in a second language. A widely cited 2023 Stanford study found popular detectors flagged essays by non-native English writers as AI far more often than essays by native speakers.
- Formulaic genres — lab reports, legal text, abstracts, product specs.
- Heavily edited text run through grammar tools.
- Very short passages, where there is too little signal.
If you are a teacher or editor, treat a high score as a reason to talk to the writer, not as a verdict.
Who uses it
- Students checking their own work before submitting.
- Writers and editors reviewing freelance or agency drafts.
- Marketers checking AI-assisted content before it goes live.
- Hiring managers reading cover letters and writing tests.
Frequently asked questions
Is the AI detector free?
Yes. It is free with no sign-up. A short video ad plays while the scan runs.
Which detector powers the score?
Each check runs a GPTZero scan, one of the most widely used AI detectors.
How accurate is it?
GPTZero is among the stronger detectors, but no detector is perfect. Short, formulaic or second-language writing can be misjudged.
Do you store my text?
No. Your text is sent for the scan and not kept afterwards. See the privacy policy.
Does it work in other languages?
GPTZero can scan several languages, and the detector is also available in Spanish, Portuguese and Indonesian. Scores are most reliable for English.