GPTZero AI Detector: Check If Text Was Written by ChatGPT
GPTZero (often searched as “GPT Zero”) scans essays, articles and emails and highlights which sentences look AI-generated — from ChatGPT, GPT-5, Gemini, Claude and more. Here’s how it works, what it costs, and how it compares to ZeroGPT.
We copy your text to the clipboard and open GPTZero — just paste it there and press Scan. Nothing is stored on this site.
Figures as published by GPTZero, checked October 30, 2026.
What is GPTZero?
GPTZero is an AI content detector that estimates whether a piece of text was written by a human or generated by an AI model such as ChatGPT, Gemini or Claude. You paste or upload text, and it returns an overall AI probability with color-coded sentences showing exactly where AI writing is likely. Launched in January 2023, GPTZero is widely used by teachers, students, publishers and recruiters, and it also offers a plagiarism checker, Google Docs writing replay and a Chrome extension.
How GPTZero Detects AI Writing
AI models tend to write in predictable, evenly-paced patterns. GPTZero’s model weighs hundreds of signals — these three are the best known.
Perplexity
How predictable each word is. Text that is consistently “easy to guess” is a classic sign of a language model.
Burstiness
How much sentence length and structure vary. Humans write in bursts; AI output is often uniform.
Style patterns
Generic, repetitive phrasing and tone that GPTZero has learned to associate with AI models.
How to Use GPTZero in 3 Steps
Paste or upload your text
Open GPTZero, paste an essay, article or email into the box, or upload a document. Scans over 10,000 characters need a free account.
Click “Scan”
GPTZero analyzes the writing with its detection model, looking at signals like perplexity, burstiness and style across the whole text.
Read the result
You get an overall AI score and color-coded sentences marking likely AI, human or mixed writing. Use it to start a conversation — not as the final verdict.
GPTZero Features at a Glance
More than a basic AI checker — GPTZero is a toolkit for proving writing is authentic.
AI Detector
Paste text or upload a file and GPTZero returns an overall AI probability plus sentence-level highlights showing which lines look machine-written.
Advanced Scan
A deeper report that explains, in plain language, why passages were flagged — useful when you need to justify a result to a student, client or editor.
Writing Replay
In Google Docs, replay how a document was written: typing patterns, copy-paste events and editing history as video-style proof of authorship.
Plagiarism Checker
Checks whether content was copied from outside sources without attribution, alongside the AI check.
Chrome Extension & Integrations
Detect AI inside Gmail, Google Docs, Google Classroom, Canvas, Zapier and more — or build on the GPTZero API.
Grammar & Writing Feedback
Free grammar checking and AI-tutor style feedback to help writers improve, not just get scored.
Trusted for the Work That Matters Most
What teachers, students, journalists and writers say about GPTZero.
In TechCrunch’s hands-on test of AI detectors, GPTZero was the one tool that classified AI-written text correctly and consistently.
Describes GPTZero as a magnifying glass that lets teachers see behind a document — and turn that into a better conversation with students.
Every student her class flagged with GPTZero later confirmed they had used AI, which made the team confident in the results.
Relies on GPTZero’s writing reports and writing-process video to show that his own documents are human-written.
Found that GPTZero’s feedback matched her own reading of a piece of writing almost line by line.
Says GPTZero has been far more accurate than other AI checkers she tried, and uses it to build trust with clients.
Paraphrased from testimonials published on GPTZero’s official website. These people are endorsing GPTZero, not this independent guide.
GPTZero vs ZeroGPT: What’s the Difference?
GPTZero and ZeroGPT are two separate AI detectors from different companies — the similar names cause a lot of confusion. Here’s how they line up.
| Feature | GPTZero | ZeroGPT |
|---|---|---|
| What it is | Dedicated AI detector and writing-verification platform (gptzero.me) | Separate AI detector with extra writing tools (zerogpt.com) |
| Sentence-level AI highlights | Yes, color-coded with explanations | Highlights suspected AI sentences |
| Writing Replay (Google Docs) | Yes — video-style authorship proof | Not a core feature |
| Classroom & LMS integrations | Google Classroom, Canvas, Chrome, API | More limited |
| Security & compliance | SOC 2 Type II, FERPA, GDPR, CCPA | Check vendor documentation |
| Free plan | Yes | Yes |
| Paid plans from | ≈ $12.99/mo (≈45% off yearly) | ≈ $9.99/mo |
| Best for | Schools, educators, publishers and teams that need explainable, defensible results | Quick, casual one-off checks |
Based on each vendor’s public information as of October 30, 2026. Features and prices change — always confirm on the official sites.
GPTZero Pricing (2026)
Start free. Upgrade only if you need more words, Advanced Scan or plagiarism checks.
Free
- Basic AI detection
- Sentence-level highlights
- Limited monthly words
- Chrome extension
Premium
- Higher monthly word limit
- Advanced Scan
- Plagiarism checking
- Writing feedback
Professional
- Highest individual limits
- Batch file scans
- Everything in Premium
Team / Enterprise
- Multiple seats
- LMS & admin tools
- SOC 2 Type II, FERPA, GDPR
- API access
Monthly prices in USD; annual billing saves about 45%. Prices checked October 30, 2026 and may change — see the official GPTZero pricing page for current offers.
Who Uses GPTZero?
GPTZero is used in thousands of colleges and by professionals wherever authentic writing matters.
Honest limitations to know
- No AI detector is 100% accurate — use results as evidence for a conversation, never as the only proof.
- Accuracy is higher on longer texts; single sentences or very short paragraphs are less reliable.
- Results are strongest for English prose. GPTZero says it de-biases its model for non-native (ESL) writers.
- Heavily edited or paraphrased AI text is harder for any detector to classify.
GPTZero Guides & Comparisons
Step-by-step tutorials and honest head-to-heads with ZeroGPT, Turnitin, Originality.ai and other AI detectors.
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Quick answers about GPTZero, GPT Zero and ZeroGPT.
What is GPTZero?
GPTZero is an AI content detector that estimates whether text was written by a human or generated by large language models such as ChatGPT, GPT-5, Gemini, Claude, Llama and DeepSeek. Launched in January 2023, it says it serves more than 20 million users, mainly in education, publishing and hiring.
Is GPTZero free?
Yes. GPTZero has a free plan for basic AI detection with a monthly word limit. Paid plans (Premium from about $12.99/month, Professional from about $24.99/month, with roughly 45% off on annual billing) add higher limits, Advanced Scan, plagiarism checks and batch uploads.
Is GPT Zero the same as ZeroGPT?
No. GPTZero (also searched as “GPT Zero”) and ZeroGPT are two different AI detectors from different companies. The names are similar, so people often mix them up. GPTZero focuses on sentence-level detection, writing replay in Google Docs, classroom integrations and enterprise compliance.
How accurate is GPTZero?
GPTZero reports 99.9% accuracy on its own benchmarks and cites third-party testing such as the RAID benchmark, where it detected 95.7% of AI texts while misclassifying about 1% of human texts. No AI detector is 100% accurate, so results should be treated as evidence, not proof.
Can GPTZero detect ChatGPT, Gemini and Claude?
Yes. GPTZero is trained to detect text from major models including ChatGPT (GPT-4, GPT-5 and newer), Gemini, Claude, Llama and DeepSeek, as well as mixed documents that combine human and AI writing.
Which languages does GPTZero support?
GPTZero fully supports English, Spanish, French, German and Portuguese, and is used in over 100 countries. Accuracy is strongest on longer English prose.
Is gptzero.chat the official GPTZero website?
No. gptzero.chat is an independent guide that reviews and explains GPTZero. The official tool runs on GPTZero’s own website; our buttons send you there through an affiliate link, which may earn us a commission at no extra cost to you.
Find Out If Your Text Was Written by AI
Paste your essay, article or email into GPTZero and get a sentence-by-sentence AI score in seconds. The free plan is enough to start.
Try GPTZero Free → See pricing