Quick answer: To use GPTZero, open the GPTZero AI detector, paste your text (or upload a .docx/.pdf file), click Scan, and read the result. GPTZero shows an overall probability that the text was written by AI and highlights individual sentences that look machine-generated. The free plan is enough to try it; you only need an account for longer scans.
This guide walks through every step — from your first scan to the Chrome extension and Google Docs Writing Replay — plus tips for reading results fairly. Last updated: October 2026.
What you need before you start
- The text you want to check. Longer samples give more reliable results; a full paragraph or essay works far better than a single sentence.
- A browser. GPTZero runs on the web, so there is nothing to install for a basic scan.
- A free account (optional). Scans over 10,000 characters, file uploads in bulk and scan history require you to sign in.
Step 1: Open GPTZero and paste your text
Go to the GPTZero homepage — the scan box is right at the top. Paste the essay, article, email or post you want to check. You can also click the upload option to add a document instead of copy-pasting.
Tip: remove reference lists, quotations from other sources and code blocks. They are not the author's own prose and can distort the score.
Step 2: Click “Scan”
Press Scan. GPTZero runs the text through its detection model, which looks at signals such as perplexity (how predictable the wording is), burstiness (how much sentence length and structure vary) and hundreds of other style patterns. Results usually appear within a few seconds.
Step 3: Read the result
GPTZero gives you two layers of information:
- An overall classification — whether the document is most likely human-written, AI-generated or a mix, with a probability score.
- Sentence-level highlights — color-coded sentences showing exactly where AI writing is most likely. This is the part that makes GPTZero useful for a conversation with a student or writer, because you can point to specific passages.
Paid plans add Advanced Scan, which explains in plain language why passages were flagged.
Step 4 (optional): Check plagiarism and writing quality
From the same dashboard you can run GPTZero's plagiarism checker to see whether text was copied from outside sources, and use the free grammar and writing feedback tools to improve a draft.
How to use the GPTZero Chrome extension
- Install GPTZero's extension from the Chrome Web Store.
- Pin it to your toolbar.
- Open Gmail, Google Docs, Google Classroom or any web page and run a scan without copy-pasting.
The extension is the fastest option for teachers grading in Google Classroom or editors reviewing submissions in the browser.
How to use Writing Replay in Google Docs
Writing Replay lets you watch how a Google Doc was written: typing patterns, large paste events and the editing timeline. For students, it is a way to prove their work is their own. For teachers, it adds context that a single AI score cannot give.
Tips for accurate results
| Do | Avoid |
|---|---|
| Scan at least a few paragraphs | Judging a single sentence |
| Scan the author's own prose only | Including quotes, citations or code |
| Look at highlighted sentences, not just the % score | Treating the score as proof |
| Combine with Writing Replay or a conversation | Punishing based on one scan |
For a deeper look at reliability, read Is GPTZero accurate? If you are deciding whether to upgrade, see our GPTZero pricing guide.
FAQ
Is GPTZero free to use?
Yes. GPTZero has a free plan for basic AI detection with a monthly word allowance. Paid plans add higher limits, Advanced Scan, plagiarism checks and batch uploads.
Do I need an account to use GPTZero?
Not for a quick scan. You need a free account for scans over 10,000 characters and to save your scan history.
Which AI models can GPTZero detect?
GPTZero is trained to detect text from ChatGPT (GPT-4, GPT-5 and newer), Gemini, Claude, Llama, DeepSeek and other large language models, including mixed human/AI documents.
Is GPTZero the same as ZeroGPT?
No — they are different tools from different companies. See our GPTZero vs ZeroGPT comparison.