The best AI detector depends on your needs (accuracy, cost, features), but based on recent tests and reviews, here are the top AI content detectors in 2025:

Top AI Detectors by Accuracy and Features

• Scribbr’s Premium AI Detector
  • Highest accuracy at 84%
  • Very low false positives
  • Detects up to 100% of GPT-4 texts and many edited AI texts
  • Provides percentage likelihood of AI content
  • Includes plagiarism check as well
  • Paid service but offers a money-back guarantee and live support

• QuillBot AI Detector (Free)
  • High accuracy at 78%
  • No false positives
  • Detects 100% of GPT-3.5 and GPT-4 texts
  • Provides percentage likelihood
  • Unlimited free checks without sign-up required

• Scribbr Free AI Detector
  • Also 78% accuracy, similar to QuillBot
  • Detects GPT-3.5 and GPT-4 texts well
  • Free and easy to use, no sign-up needed

• Originality.ai
  • Commercial tool with up to 98% accuracy in its Lite model
  • Strong performance in AI detection and plagiarism checking
  • Paid service with usage credits

• GPTZero
  • Known for accuracy and detailed writing analysis using perplexity and burstiness metrics
  • Free classic detection for up to 10,000 words/month; paid plans start at $15/month
  • Sometimes less clear in results compared to others

• Winston AI
  • Claims very high accuracy (99.98%) but independent tests show mixed results (~42%)
  • Good integration options for businesses
  • Recommended for premium use but verify accuracy for your needs

Summary Table

Tool| Accuracy| Free Option| Notes
---|---|---|---
Scribbr Premium| 84%| No| Best overall accuracy, paid
QuillBot| 78%| Yes| High accuracy free tool
Scribbr Free| 78%| Yes| Similar to QuillBot
Originality.ai| Up to 98% (Lite)| No| Paid, commercial-grade
GPTZero| Moderate (~52%)| Yes| Good analysis features, paid version
Winston AI| Mixed (~42%)| Yes| Good integrations, accuracy varies

Conclusion

For the most accurate detection, Scribbr’s premium AI Detector is currently the best choice, especially if you want reliable results and additional plagiarism checking. For free options, QuillBot and Scribbr’s free detector offer strong performance without cost. Originality.ai is also a strong commercial alternative. Tools like GPTZero and Winston AI provide useful features but may have variable accuracy depending on the test