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AI Detector

Free AI Detector — Spot AI-Generated Text in Seconds.

Paste your text and get a 0-100 AI probability score, sentence-level highlights ranked by suspicion, and a Humanization Score that tells you how natural it reads. One scan covers GPT-4, Claude, Gemini, and Llama.

No credit card · No signup for your first scan · Up to 99.2% accuracy in our internal benchmark

TextSight AI Detector results panel showing AI probability score, Humanization Score, and sentence-level highlights
Run a scan

Drop your text in. Get an instant verdict.

Paste your draft, upload a PDF or DOCX, or point at a URL. We score it across 50+ language signals trained on GPT-4, Claude 3.x, Gemini, and Llama 3 — and ship a one-click humanizer in the same scan to fix what's flagged.

Open the AI Detector →
How it works

Three steps. Under three seconds.

1

Paste, upload, or link

Drop text directly, upload a PDF or DOCX file, or paste a URL. Anything under 5,000 characters runs free. Larger drafts run on paid plans.

2

We score across 4 model families

50+ language signals — burstiness, perplexity, lexical patterns, and structural markers — checked against OpenAI, Anthropic, Google, and Meta output fingerprints.

3

Score + highlights + one-click humanizer

You get an overall AI-probability score, a Humanization Score, sentence-level highlights ranked by suspicion, and a built-in humanizer that rewrites only the flagged sentences.

Built for

Who uses the AI Detector

Students checking essays

Run your draft before submission. See which sentences look AI-generated and rewrite them in the same scan — without uploading to a third-party humanizer first.

Writers verifying authenticity

Check guest posts and ghostwritten drafts before publishing. The Humanization Score gives you a measurable benchmark to track improvements as you rewrite.

Educators reviewing submissions

Sentence-level highlights give you specific evidence to discuss with students — not a single overall score that's hard to defend.

SEO agencies auditing client content

Bulk-scan deliverables before they ship. API access on the Business plan ($29.99/mo) covers 10,000 calls/mo — about 6× cheaper than Originality.ai's Enterprise tier.

Accuracy

How accurate is the detection?

Up to 99.2% accuracy in our internal benchmark against GPT-4, GPT-4o, Claude 3.x, Gemini, and Llama 3 outputs. Results may vary with content type, writing style, AI model, and editing level. AI detection is probabilistic — no detector is perfect, and we publish our caveats openly.

What works well: long-form English text (100+ words), recent commercial models (GPT-4/4o, Claude 3.5/3.7, Gemini, Llama 3), and unedited or lightly edited AI output.

Where to be cautious: short snippets (under 50 words), heavily human-edited AI text, non-English languages, and text that intentionally mimics a specific human author's voice. We flag low-confidence scores in the result so you know when not to rely on them.

Read the full methodology →
Questions

Frequently asked

How does the AI detector work?

TextSight analyzes your text against signals trained on GPT-4, GPT-4o, Claude 3.x, Gemini, and Llama 3 outputs. It returns an overall AI-probability score (0-100), sentence-level highlights ranked by suspicion, and a Humanization Score that tells you how natural the text reads. The scan typically completes in under three seconds.

Is the AI detector free?

Yes. The free tier gives you 3 scans per day with the same detector and Humanization Score as the paid plans. No credit card and no signup are required for your first scans. Higher daily limits start at $9.99/mo on the Starter plan.

How accurate is the detection?

Up to 99.2% accuracy on our internal benchmark of GPT-4, Claude 3.x, Gemini, and Llama 3 outputs. Results may vary with content type, writing style, AI model, and editing level. AI detection is probabilistic — read /accuracy-methodology for our test setup, false-positive rate, and the caveats we apply to every score.

Can it detect ChatGPT, Claude, and Gemini text?

Yes. The detector is trained across all four major model families — OpenAI (GPT-3.5, GPT-4, GPT-4o), Anthropic (Claude 3, 3.5, 3.7), Google (Gemini), and Meta (Llama 3). Newer model releases are added to the training set as they ship. We also publish a dedicated ChatGPT detector page focused on OpenAI-specific signals.

What's the difference between AI detection and AI humanization?

Detection tells you which parts of your text read as AI-generated. Humanization rewrites the flagged sentences so they read more naturally — TextSight ships both in the same scan. After you get a score, one click runs the AI Humanizer on just the flagged sentences and re-scores.

Does it work on non-English text?

The detector is English-focused. It works on other Latin-alphabet languages but accuracy drops outside English. For comprehensive multilingual detection, dedicated multilingual tools are a better fit.

Is my text stored?

Free scans are processed in-memory and discarded; we keep only the score and metadata in your history. Paid plans give you a 30-day to unlimited retention window for the full text — see /privacy for the full retention table.

Does short text work?

The detector needs at least 50 words of signal to be reliable. 100+ words is the recommended minimum for confident scoring. Below 50 words, the score is shown but flagged with low confidence.

Related tools

AI Humanizer →
Rewrite flagged AI text in one click
Humanization Score →
The 0-100 metric on every output
ChatGPT Detector →
Tuned for OpenAI-specific signals
Accuracy methodology →
How we test and what to expect

Ready to Scan Your Draft?

Detect AI. Fix AI. One tool. 3 free scans/day, no card required.