AI detector made to
Preserve what's human.

GPTZero is the first and leading AI detector that allows you to identify specific content in a document or text that has been generated by a large language model (LLM)such as ChatGPT. Founded in January 2023GPTZero has served over 10 million users to date and works with 100+ organizations in educationhiringpublishinglegal and more.

AI detectors work by looking for patterns in text that are more likely to have been written by a machine than a human. The most common factors they look for include: Perplexity: Is the writing obviously predictable? Burstiness: How much variation is there in the sentence length and ? Style: Is the tone and writing overly generic or repetitive? GPTZero uses its own proprietary model that takes hundreds of factors into consideration and boasts the highest detection accuracy in the industry

Yes. Independent benchmarkslike our partners at Penn State's AI Research Laband our own large-scale testing show that GPTZero is the most accurate AI detectorwith a 99% accuracy rate when spotting AI-generated text vs. human writing. This means we correctly classify AI writing 99 out of 100 times and keep misclassification of text to an absolute minimum. Our results were further validated on RAIDa comprehensivethird-party benchmark where GPTZero was shown to be the most accurate AI detector in North Americadetecting 95.7% of AI texts while only incorrectly predicting 1% of human texts as AIan accuracy that jumps to over 99% when filtering to modern LLMs like GPT4. Unlike many competitorsGPTZero can reliably detect "mixed documents" (where human and AI writing are combined) with a 96.5% accuracy rate. While no AI detector can ever truly be 100% perfectwe are committed to being a leader in responsible adoption of AI generation and AI detection technologies.

You can start using GPTZero straight away in 3 easy steps: Paste Text or Upload Document: Paste in raw text or upload your file for review and press ‘Scan’. For scans over 10,000 characterscreate a free account first. See Your Results: GPTZero will suggest what percentage of your text is likely to be AI-generated and highlight the specific phrases it has detected. Download our Chrome Extension for Google Docs and web: View AI detection and typing pattern metrics on any pageallowing you to spot AI-created content with ease.

GPTZero is the most trusted AI content checker in educationboth for teachers and students who use GPTZero to guide conversations on academic integrity and writing improvement. GPTZero is used in over 3500 colleges and 100s of institutions. We also serve publishersrecruiterscopy-writersmarketers and businesses where authentic and quality writing truly matters.

No. GPTZero works across a wide range of AI language modelsincluding but not limited to ChatGPTGPT-5GPT-4GPT-3GeminiClaudeLlamaDeepseekand AI services based on those models. Our detector is designed for the highest accuracy rate regardless of which model may have produced the text. In our latest model releasewe’ve updated the majority of our training dataincluding more AI documents from: OpenAI – GPT4.1,GPT4.1-minio3o3-mini Gemini – 2.5 Pro2.5 Flash2.5 Flash-Lite ClaudeSonnet 4 as well as a few other models.

GPTZero fully supports EnglishGermanPortugueseFrench and Spanish with industry-leading accuracy. We are also constantly used in many other languages and in over 100 countries.

GPTZero is consistently rated the most accurate and reliable AI detector across various use cases. Reliability: In 2025G2 ranked GPTZero the #1 most trusted and reliable AI toolabove Grammarly. Accuracy: GPTZero is the most accurate AI detector with 99% accuracy rates across diverse datasetsindependently reviewed by AI labs at top institutions. Independent reviewersincluding Tom’s Guidetesting all popular detectors named GPTZero the most accurate. Best Interpretability: GPTZero is the only detector that explains exactly why text is AI with natural language. GPTZero also has the most accurate sentence-level AI detectionwith color-coded highlights on exactly where AI is used in an essay.

No AI detector is 100% accurateand AI itself is changing constantly. Results should not be used to punish or as the final verdict. Accuracy improves with longer inputs (document-level results are stronger than paragraph or sentence-level) and is strongest on English prose. GPTZero is the only AI detector de-biased for ESL (English Second Language) learnerswhich many competitors do not take into account. We repeatedly train our model to reduce false positive rate for ESL writing to 1%. We also monitor our datasets to transparently prevent any bias in AI detection training data.