An AI detector is a tool that estimates whether a human or an AI wrote a piece of text. It studies writing patterns, sentence structure, and word choice to spot the habits of machine-generated writing. This free AI detector gives you an instant, pattern-based score in your browser. No sign-up. No cost. Just paste your text and check it today.
Free AI Detector
Paste your text below. The checker analyzes writing patterns, sentence structure, and word choice — instantly, in your browser. Free, with no sign-up.
How does this AI detector work?
This AI detector runs five writing-pattern checks on your text. It measures sentence-length variety, average word length, repeated AI-style phrases, paragraph uniformity, and vocabulary repetition. Each check feeds an AI-likelihood score. You see the score band plus the exact signals behind it — full transparency, no black box.
Here is what each check looks at:
- Sentence-length variety (burstiness). Human writing mixes short punches with long, winding sentences. Machine text keeps a steadier beat.
- Average word length. AI drafts lean on longer, formal words. Everyday human writing uses shorter words.
- AI-style phrases. Words and phrases models overuse — delve, furthermore, moreover, in conclusion, it is important to note, and more.
- Paragraph uniformity. Evenly sized paragraphs suggest templated output. Humans write lopsided blocks.
- Vocabulary repetition. A small pool of repeated words is a classic machine tell.
How accurate is it?
The checker flags common AI writing patterns. Formal, heavily edited, or very short text can affect the score, so treat it as a strong indicator, not final proof. Like the leading detectors, it reads patterns — it does not certify authorship. Use it as a fast first screen, then apply your own judgment.
Professional detectors like GPTZero build on the same pattern ideas, adding trained models on top. Our Chat GPT detector guide explains how these tools work in practice.
Is this AI detector free?
Yes — completely free, with no sign-up and no word-count limits. Every check runs in your browser with plain JavaScript, so your text never leaves your device and there is no server cost to pass on to you. Free means free: no trial, no account, no catch.
What text gives false positives?
Formal, polished writing can raise the score: academic essays, press releases, and legal text often use steady rhythms and standard transitions. Heavily edited copy and very short samples can also shift the result. That is why the score is a guide, not a verdict — context matters.
How to use this AI detector
- Paste your text into the box above — at least 50 words for a stable reading.
- Watch the live word count, then click “Check Text”.
- Read your score band: Likely human-written, Mixed signals, or Likely AI-generated.
- Review the listed signals to see exactly what shaped the score.
Who should use this free AI detector?
Teachers reviewing student work. Editors screening submissions. Hiring managers checking writing samples. Students reviewing their own drafts before they submit. Bloggers who want a second opinion on guest posts. Anyone who works with words and wants a fast, free first screen.
Get the most reliable score
A few habits give you the cleanest reading:
- Use 50 or more words. Longer samples give steadier signals.
- Paste plain text, not headlines or bullet fragments.
- Compare against a text you know is human to calibrate.
- Remember: formal or heavily edited writing can shift any pattern score.
What this free checker does not do
- It makes no 100%-accuracy claim. No serious checker does.
- It is not affiliated with OpenAI or Turnitin.
- It cannot prove authorship. It estimates likelihood from patterns.
- It works best on English text of 50 or more words.
- Paraphrased or human-edited AI text is harder for any pattern check to flag.
AI detector FAQs
Can an AI detector detect ChatGPT text?
Yes, up to a point. ChatGPT writing often shows steady sentence rhythms, standard transitions, and favorite phrases — exactly the patterns this checker measures. A careful human edit can mask them, so treat the score as a strong indicator, not final proof.
Are free AI detectors accurate?
The checker flags common AI writing patterns. Formal, heavily edited, or very short text can affect the score, so treat it as a strong indicator, not final proof.
How do I check if text is AI-generated?
Paste the text into the checker above and click “Check Text”. For important calls, compare the result with a known human sample — and always combine the score with your own judgment.
Can AI detectors be wrong?
Every detector can misread a text. Formal human writing can look machine-like, and polished AI text can look human. That is why no checker should be the only proof. Use the score as a guide, not a verdict.
Does this AI detector store my text?
No. Everything runs in your browser with JavaScript. Your text never leaves your device, so there is nothing to store, leak, or sell.
What is the best free AI detector?
The best checker is one that shows its reasoning. This tool lists every signal behind its score, runs entirely in your browser, and costs nothing. For a deeper look at the field, read our article on AI content detection technology.