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Free AI Content Detector

See how likely a text is AI-written, section by section. Up to 5,000 words.

Calculated in your browser

0 / 5,000 words

Use the result as a guide, not proof. No AI detector is 100% accurate. Edited or paraphrased AI text can pass as human, and formal, technical or non-native English can sometimes look AI-like. Never use a score alone to accuse someone.

AI Content Detector at a glance

Price
Free
Sign-up
Not needed
Privacy
Runs in your browser; nothing is sent
Word limit
5,000 words per check
Language
English (best accuracy)
AI model
RoBERTa detector (MIT), on your device
Last updated
11 October 2026

What it can do

  • Detects ChatGPT and other AI-written text
  • Up to 5,000 words per check — long essays and articles
  • Highlights which sections look AI-written
  • Explains the writing signals behind the result
  • Runs in your browser; text is never uploaded

Help & FAQ

How to use the AI Content Detector

How to check text for AI writing

  1. Paste your text into the box — up to 5,000 words per check.
  2. Select Detect AI. The first time, the detector downloads to your browser.
  3. Read the AI score and verdict, and see which sections are highlighted as likely or possibly AI-written.
  4. Open the writing signals to see what makes the text read as AI-like.

How it works

Each section of your text is checked by an open-source AI detection model (TMR, a RoBERTa model trained on the RAID benchmark), running on your device. The overall score is the average across sections, weighted by length. The writing signals — uniform sentence lengths, typical AI phrases, heavy use of transitions and repetitive vocabulary — are adapted from the open-source ai-text-detector project and explain the style; they don't decide the score.

Want to count words or estimate reading time? Use the Word Counter.

Is there a word limit?

You can check up to 5,000 words at a time — enough for most essays, reports and articles — as often as you like, for free. Longer texts are split into sections of about 150–330 words, and each section is checked on its own. For a longer document, check it in parts.

Is my text uploaded or stored?

No. The AI detection model runs inside your browser, on your own device. Your text never reaches SomethingTools or anyone else, and nothing is saved after you close the page.

How accurate is it?

The detector uses an open-source RoBERTa model (TMR, MIT licence) trained on the RAID benchmark. We tuned its cut-offs to avoid false alarms: on public test data of real human answers and ChatGPT answers, it flagged about 3–7% of human texts and caught about 90% of AI texts. Real-world accuracy is lower for heavily edited or paraphrased AI text, newer AI models, and non-English writing.

Can I use the result to prove someone used AI?

No. No AI detector can prove authorship. Formal, technical or non-native English can sometimes look AI-like, and AI text that has been edited can look human. Treat the result as one signal, compare with the writer's other work, and talk to them before drawing conclusions.

Which AI tools can it detect?

It is trained to spot text from many large language models, including the kind of writing produced by ChatGPT, GPT-4, Claude, Gemini, Llama and similar tools. It works best on English text of at least 50 words.

Why does the first check take longer?

The first time, your browser downloads the detection model (about 140 MB including the engine) from SomethingTools. It is kept by your browser, so later checks start straight away.