There are dozens of AI detectors now. Here's how the major ones actually perform based on testing and user reports.
GPTZero
Best for: Quick free checks
Accuracy: ~85%
Pros: Free tier available, fast results, widely known
Cons: Higher false positive rate, basic analysis
Turnitin AI Detection
Best for: University submissions (if your school uses it)
Accuracy: ~98% (claimed)
Pros: Integrated with existing plagiarism checks, detailed reports
Cons: Institutional access only, not available to students directly
Originality.ai
Best for: Content creators and publishers
Accuracy: ~94%
Pros: Also checks for plagiarism, team features, API access
Cons: Paid only, can be expensive for high volume
Copyleaks
Best for: Business and enterprise use
Accuracy: ~91%
Pros: Multi-language support, LMS integrations
Cons: Primarily B2B focused, pricing not transparent
Writer.com AI Detector
Best for: Quick free checks
Accuracy: ~80%
Pros: Completely free, no signup required
Cons: Less accurate than competitors, limited features
Sapling AI Detector
Best for: Developers and API users
Accuracy: ~85%
Pros: Good API, sentence-level detection
Cons: Less known, smaller training dataset
The Accuracy Problem
Here's what most people don't understand: no AI detector is 100% accurate. They all have:
- False positives (flagging human text as AI)
- False negatives (missing actual AI text)
- Inconsistent results between runs
The technology is fundamentally probabilistic. It makes educated guesses, not definitive judgments.
What This Means
If you're using AI writing tools, don't rely on one detector to test your work. Check with multiple tools. And use a proper AI humanizer to ensure consistent results across all detectors.