How It Works
Discover the science and technology behind Phrasly AI Detector. Learn how we analyze text to identify AI-generated content with accuracy and transparency.
3 Simple Steps to Detect AI Content
Using Phrasly AI Detector is straightforward and takes just seconds
Paste Your Text
Copy and paste the text you want to analyze into our detector tool. There’s no need to create an account or provide any personal information.
- Minimum 80 words required
- 200+ words recommended for best accuracy
- No word count limit on free plan
- Your text never leaves your browser
Click “Check for AI”
Our advanced algorithm analyzes your text using multiple detection methods. The analysis happens entirely in your browser for complete privacy.
- Processing takes 2-3 seconds
- Client-side analysis ensures privacy
- Multiple AI models detected (GPT, Claude, Gemini)
- Real-time probability calculation
Review Your Results
Get a comprehensive analysis including an overall AI probability score and sentence-by-sentence breakdown highlighting specific patterns.
- Overall AI probability percentage (0-100%)
- Clear verdict with explanation
- Sentence-level analysis with color coding
- Recommendations based on results
The Technology Behind Detection
Machine Learning Models
Our detector uses advanced machine learning algorithms trained on millions of text samples from both human writers and AI language models including GPT, Claude, Gemini, and Llama.
Perplexity Analysis
We measure perplexity — how predictable or “surprised” a language model would be by the text. AI-generated content tends to have lower perplexity (more predictable patterns) compared to human writing.
Burstiness Detection
Burstiness measures variation in sentence length and structure. Human writing naturally varies more, while AI tends to produce more uniform sentence patterns. We analyze this variance to identify AI content.
Pattern Recognition
Our algorithm identifies common AI writing patterns and phrases like “it’s worth noting,” “delve into,” “in today’s world,” and other markers that appear more frequently in AI-generated text.
Statistical Analysis
We perform deep statistical analysis on word choice, sentence structure, punctuation patterns, and linguistic features that distinguish human creativity from AI generation.
Multi-Factor Scoring
Rather than relying on a single metric, we combine multiple detection methods into a comprehensive probability score. This multi-layered approach improves accuracy and reduces false positives.
Understanding Your Results
Our detector provides a probability-based assessment, not a definitive yes/no answer. Here’s how to interpret your results:
AI Probability Scores:
80-100% (Highly Likely AI-Generated): The text exhibits strong patterns typical of AI language models. Multiple indicators suggest AI authorship, including low perplexity, common AI phrases, and uniform structure.
50-79% (Possibly AI-Assisted): The text shows mixed signals. Some sections appear AI-generated while others seem human-written. This often indicates AI assistance with human editing, or formal writing styles that mimic AI patterns.
20-49% (Likely Human with Possible AI Edits): Mostly human-written content with occasional AI-like characteristics. May indicate minor AI assistance for specific sections or just formal writing style.
0-19% (Likely Human-Written): The text exhibits natural variation, creativity, and unpredictability typical of human writing. Few to no AI indicators detected.
Important: No AI detector is 100% accurate. Use results as one data point among many, never as sole evidence for important decisions.
Sentence-Level Analysis:
Our tool highlights individual sentences with color coding:
- Red (70-100%): High probability of AI generation
- Yellow (40-69%): Moderate probability, uncertain
- Green (0-39%): Low probability, likely human
This breakdown helps you identify specific sections that may need attention or revision.
Pro Tip: For most accurate results, submit at least 200 words. Shorter texts don’t provide enough statistical data for reliable analysis.
Limitations & Best Practices
False Positives
Formal writing, non-native English speakers, and highly structured content may be incorrectly flagged as AI-generated. Always consider context and other factors.
Edited AI Content
AI-generated text that has been significantly edited by humans may evade detection. Our tool works best on unedited or lightly edited content.
Language Support
Currently optimized for English text. Other languages may produce less accurate results due to different linguistic patterns and training data limitations.
Text Length Matters
Longer texts (200+ words) provide more data points for analysis. Very short texts may not contain enough information for accurate detection.
Evolving AI Models
As AI writing tools improve and change, detection methods must adapt. We continuously update our algorithms to keep pace with new AI models.
Combine with Human Judgment
Use detection results as guidance, not proof. Always combine AI detection with human review, context analysis, and other verification methods.
Ready to Try It?
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