Free AI Content Detector
Paste any text below to check whether it reads as AI-generated. If it gets flagged, run it through the humanizer to fix it.
What is an AI content detector?
An AI content detector is a tool that estimates whether a piece of text was written by a large language model (like ChatGPT, Gemini, or Claude) or by a human. It doesn't "know" the answer for certain — no detector can — it scores statistical patterns in the writing and reports a probability.
Humanizer.gg's detector works the same way. Paste in any text above and it returns an AI-likelihood score, a word count, and a plain-language verdict, so you can check your own writing before a teacher, editor, client, or detector like Turnitin catches something you didn't expect.
How AI detection actually works
Detectors don't read for meaning. They measure two statistical properties that tend to differ between machine and human writing.
Perplexity
A measure of how predictable each word choice is. Language models tend to pick the statistically most likely next word, which produces low perplexity. Human writers make less predictable choices, producing higher perplexity.
Burstiness
A measure of sentence-length variation. Human writing naturally mixes short fragments with long, winding sentences. AI writing tends toward a more uniform rhythm, sentence after sentence.
This tool scores both signals and combines them into the single AI-likelihood percentage you see above. No detector, including this one, is 100% accurate — read our full testing methodology for the honest details.
Who checks their text with an AI detector
Anyone who submits, publishes, or sends writing under their own name has a reason to check it first.
Students
Check an essay draft before Turnitin or GPTZero does.
Educators
Get a quick second signal on a submission worth a closer look.
Editors & publishers
Screen freelance submissions before they go under a trusted masthead.
Content & SEO teams
Spot-check AI-assisted drafts before they're published at scale.
Which AI models can it flag?
The underlying signals (perplexity and burstiness) aren't tied to one model's fingerprint, so this detector isn't limited to spotting a single chatbot. It works on text drafted with ChatGPT and GPT-4o, Google Gemini, Anthropic Claude, Microsoft Copilot, Meta Llama, and most other mainstream language models, since they all tend to produce the same underlying statistical patterns.
Common questions
How accurate is this AI detector?
No AI detector is 100% accurate, this one included. It scores statistical patterns, not certainty, and can produce false positives on formulaic human writing and false negatives on heavily-edited AI text. Treat the score as a signal, not a verdict.
Can it detect ChatGPT, Gemini, and Claude text specifically?
Yes. It doesn't fingerprint one specific model — it looks for the perplexity and burstiness patterns common across mainstream language models, so it works across ChatGPT, Gemini, Claude, Copilot, Llama, and similar tools.
Is my text stored or shared?
The text you paste is sent to our detection engine to generate your score and isn't used to train third-party AI models. See our privacy policy for full details.
My text got flagged as AI-written. Now what?
If you used AI to draft or polish the text and want it to read naturally in your own voice, run it through the humanizer, then check it again here.
Is this free to use?
Yes, the detector above is free with no account required.
Detectors we're built to match
We benchmark our own humanizer against these detectors, the same industry names our detection engine is designed to reason about.
Flagged as AI? Fix it in seconds.
Run flagged text through our humanizer to restore natural rhythm and phrasing while keeping your meaning intact.