AI Content Detector — Free Check if Text is AI Generated
Detect AI-generated text with perplexity, burstiness, and vocabulary analysis. Get sentence-level highlights. All processing local, text never leaves browser.
Features
- ✓Analyze text for AI-generated content using multiple statistical metrics
- ✓Perplexity analysis — measures how predictable the text is to language models
- ✓Burstiness analysis — detects uniform sentence patterns typical of AI
- ✓Vocabulary diversity scoring — Type-Token Ratio and unique word analysis
- ✓AI keyword detection — identifies phrases commonly used by LLMs
- ✓Sentence-level highlighting — color-code sentences by AI probability
- ✓Real-time analysis — results update as you type or paste text
- ✓Supports both English and Chinese text analysis
- ✓Copy or export analysis results for documentation
- ✓All processing happens locally — your text never leaves your browser
How to Use
- 1Paste or type text into the input area (minimum 100 characters recommended).
- 2Click 'Analyze' or wait for automatic analysis to complete.
- 3Review the overall AI probability score at the top.
- 4Check individual metrics: Perplexity, Burstiness, Vocabulary Diversity, AI Keywords.
- 5Read the detailed explanation for each metric to understand the analysis.
- 6Review sentence-level highlights — red indicates higher AI probability.
- 7Copy the analysis report for your records or documentation.
- 8For best results, use texts longer than 255 characters.
Frequently Asked Questions
How accurate is this detector?
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This tool uses statistical heuristics (perplexity, burstiness, vocabulary analysis) which provide reasonable accuracy for detecting AI-generated text. However, it is not as accurate as deep learning models like GPTZero. Use it as a screening tool, not a definitive judge. For high-stakes decisions, combine with other verification methods.
What is perplexity?
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Perplexity measures how 'surprised' a language model would be by the text. AI-generated text typically has lower perplexity because LLMs tend to choose the most probable words, making the text more predictable. Human text usually has higher perplexity due to more varied and creative word choices.
What is burstiness?
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Burstiness measures the variation in sentence length and complexity. Human writing tends to have high burstiness — mix of short and long sentences, complex and simple structures. AI text often has low burstiness — sentences are more uniform in length and structure.
Can this detect all AI-generated content?
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No. This tool works best with: 1) Texts longer than 255 characters, 2) English or Chinese text, 3) Texts generated by standard LLMs (GPT, Claude, etc.). It may struggle with: paraphrased AI text, mixed human-AI text, or text from specialized/domain-specific LLMs.
Is my text uploaded to any server?
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No. All analysis happens entirely in your browser using JavaScript. Your text is never sent to any server, stored, or transmitted. This makes the tool suitable for confidential documents, student papers, and sensitive content.
Why is my text flagged as AI when I wrote it myself?
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False positives can occur when: 1) You use formal/academic writing style, 2) Your text follows predictable patterns, 3) You use common phrases or structures, 4) The text is short (less reliable). If you're confident the text is human-written, the detector may be wrong.
What AI keywords does the tool detect?
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The tool detects phrases commonly used by LLMs like 'Furthermore', 'In conclusion', 'Moreover', 'It is important to note', 'Delve into', 'Tapestry', 'Landscape', 'Realm', 'Embark', etc. These are not definitive proof of AI generation but are statistical indicators.
Does it work with Chinese text?
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Yes. The tool supports both English and Chinese text analysis. For Chinese, it uses character-level analysis and Chinese-specific tokenization via the browser's built-in Intl.Segmenter API.
What should I do with the results?
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Use the results as one data point in your evaluation: 1) High AI probability + clear patterns → investigate further, 2) Low AI probability → likely human-written, 3) Mixed results → use judgment. Never rely solely on automated detection for important decisions.