Most AI detectors only catch ChatGPT. GPTOne is the only free detector trained and benchmarked on ChatGPT, Claude, Gemini, GPT-4, and GPT-5 so nothing slips through.
Other tools were built when ChatGPT was the only AI in the room. GPTOne was built for 2026, where ChatGPT, Claude, Gemini, and their latest versions are all on the table.
Full coverage across Claude 3 Haiku, Claude 3.5 Sonnet, Claude 3.5 Haiku, Claude Opus 4, Claude Sonnet 4 and Claude Haiku 4. Anthropic's models produce stylistically varied text that GPT-focused detectors consistently miss.
99.99% accuracyFull coverage from Gemini 1.0 Pro through Gemini 1.5 Flash, Gemini 2.0 Flash and Gemini 2.5 Pro. Google's models power writing in Docs, Gmail and Workspace tools your users rely on daily.
99.99% accuracyFull OpenAI family coverage including GPT-3.5, GPT-4, GPT-4o, GPT-4o mini, GPT-4.5, o1, o3 and GPT-5. The broadest ChatGPT detection available in any free tool.
99.99% accuracyA false positive rate under 5% across all model families keeps innocent writers protected. Non-native English speakers and formal academic styles are calibrated for, not penalized.
<5% false positivesNo account, no plugins, no waiting. GPTOne's multi-model classifier runs your text against four AI model families simultaneously.
Copy any essay, cover letter, blog post, or document into GPTOne's free detector. No formatting required — plain text works best.
GPTOne's classifier checks for statistical patterns specific to ChatGPT, Claude, Gemini, GPT-4, and GPT-5 simultaneously not just one model family at a time.
You receive an overall AI probability score plus highlighted sections showing exactly which passages drove the score so you know where to look, not just what the number is.
Use the result as a first-pass signal. For high-stakes decisions, combine with workflow guidance in our detection guides for educators, HR teams, and content platforms.
Most AI detectors report one blended accuracy figure. GPTOne is the only free tool that publishes separate benchmarks for each model family because that is the only way to verify the claim.
| Detector | ChatGPT accuracy | Claude accuracy | Gemini accuracy | False positive rate | Trained on Claude | Trained on Gemini | Model benchmarks | Free to use |
|---|---|---|---|---|---|---|---|---|
| GPTOne Best | 99.99% | 99.99% | 99.99% | <5% | ✓ | ✓ | ✓ Published | ✓ Full access |
| GPTZero | ~94% | ~76% | ~72% | 6.8% | Partial | ✗ | ✗ Blended only | Limited tier |
| Copyleaks | ~91% | ~79% | ~74% | 5.1% | Unconfirmed | ✗ | ✗ Blended only | Limited tier |
| ZeroGPT | ~89% | ~71% | ~68% | 8.4% | ✗ | ✗ | ✗ Not published | ✓ Full access |
Competitor figures are estimates based on GPTOne's internal comparative benchmark testing across 1,400 samples and independently reported user studies. GPTOne figures reflect internal benchmark data. No tool has been independently peer-reviewed.
ChatGPT, Claude and Gemini show up in classrooms, hiring pipelines, and content workflows every day. GPTOne gives every team the coverage they need.
Students use ChatGPT, Claude and Gemini daily. GPTOne's section-level highlighting tells you exactly which paragraphs flagged not just a single document score. Use it to open a review process, not to render a verdict.
Academic integrityGemini is embedded in Google Docs. ChatGPT and Claude are both widely used for cover letter drafting. GPTOne detects all three and keeps false positive rates below 5% so strong candidates are not wrongly screened out.
Hiring screeningContributor content from ChatGPT, Claude or Gemini shows different patterns than ChatGPT content. GPTOne's multi-model scanning gives editorial teams a complete picture not just the ChatGPT slice of the AI writing problem.
Content QAWhen policy or regulation requires verification that content is human-authored, you need a detector that covers all major AI writing tools not just the one in the headlines when the policy was written.
ComplianceComplete model coverage
Every major AI model family in one free tool. Follow the links below for model-specific detection guides.
Covers DeepSeek V2, V3, R1 and Grok 1, 2, 3. The fastest-growing AI models that most detectors were not built for.
View DeepSeek and Grok detector →Covers Llama 4, Mistral Large, Qwen 3 and Microsoft Phi 4. The open-source models now embedded in academic and enterprise tools.
View Llama and Mistral detector →The only free AI detector that covers every major model family in active use today. No account. No cost. Results in seconds.
Run a free multi-model AI scanFree forever for core detection · No sign-up required · All ChatGPT models · All Claude models · All Gemini models