GPTZero is an AI content detector that scans text and estimates the likelihood it was written by an AI model such as ChatGPT, Gemini, or Claude, highlighting individual sentences it flags as machine-generated. It's built primarily for teachers and administrators checking student work, but writers, recruiters, and publishers also use it to verify that text is human-written before it goes out under someone's name.
What does GPTZero do?
You paste text or upload a document, and GPTZero returns an overall AI-generated score along with sentence-level highlighting that shows which parts of the text triggered its detection model. The tool was originally built by a Princeton student in January 2023 and has grown into a suite of products that go beyond basic detection, including a hallucination checker that verifies citations and a plagiarism checker that flags text copied from outside sources.
Beyond scanning pasted text, GPTZero offers a Chrome extension that scans content as you browse, a Google Docs integration for verifying your own writing process, and direct integrations with Canvas and Google Classroom for schools that want AI detection built into their existing coursework tools.
Core features
- Sentence-by-sentence AI detection that highlights exactly which parts of a document look machine-generated.
- An Advanced AI Scan mode for more detailed probability breakdowns on longer documents.
- A Hallucination Detector that checks citations and academic sources for accuracy.
- A Plagiarism Checker that compares submitted text against outside published sources.
- Authorship Verification with writing replay, letting a writer prove a document was typed in real time rather than pasted.
- A Chrome extension and Google Docs add-on for scanning content without leaving your browser.
- Canvas and Google Classroom integrations built for academic institutions.
- An API and Zapier integration for developers who want to build AI detection into their own workflows.
Use cases
Teachers use GPTZero to review flagged student submissions as a starting point for a conversation rather than an automatic accusation, since the tool itself cautions that results should not be treated as a final verdict. Over 3,500 colleges reportedly use some form of GPTZero in their academic integrity process.
- A writer or freelancer running their own draft through GPTZero before submitting it, to catch phrasing that reads as overly generic or AI-typical.
- A publisher or editor screening submitted articles for undisclosed AI-generated content.
- A recruiter checking whether a written interview response or cover letter was likely written by a language model.
Pricing
GPTZero offers a free tier for basic scans up to 10,000 characters without an account. Paid Professional plans are billed per seat with a discount for annual billing over monthly, and GPTZero also sells Team and Enterprise plans with shared credits and unified billing for organizations buying multiple seats at once. Exact per-seat pricing is not listed publicly and requires selecting a plan or contacting sales for current rates.
How to use GPTZero
- Go to gptzero.me and paste text directly into the scan box, or upload a document.
- Click Scan to get an overall AI-generated score with sentence-level highlights.
- Install the Chrome extension if you want to scan content as you browse the web.
- Connect the Google Docs or Canvas integration if you're reviewing student work at scale.
- Create a free account if your text exceeds the 10,000-character limit for anonymous scans.
- Upgrade to a paid plan for higher usage limits, the Advanced AI Scan, or team-wide seats.
Frequently asked questions
Is GPTZero accurate?
GPTZero reports high accuracy on independent benchmarks, though like every AI detector it is not perfect and results should be treated as a signal rather than definitive proof.
Which AI models can GPTZero detect?
It is trained to recognize output from ChatGPT, GPT-4 and newer OpenAI models, Gemini, Claude, Llama, and Deepseek, among others.
Can GPTZero detect a mix of human and AI writing?
Yes, it is designed to handle mixed documents where AI and human writing are combined, flagging the AI portions specifically.
Is GPTZero free?
Yes, there is a free scan option for shorter documents, with paid plans available for higher volume, team accounts, and additional products like the Hallucination Detector.
Learn more at GPTZero.