GPT Detector

See if a text comes from GPT-3, GPT-4 or ChatGPT.

Not sure if a text is original or AI plagiarism? Check it here!

Paste in your text and click 'Check'.
Example: text written by a human and ChatGPT

Frequently asked questions about the GPT Detector

Is your question not here? Contact us at

What are the GPT Detector's key features?

🎯  Probability score See how likely it is that a text was generated with GPT.
🙌  Free to useCompletely free ChatGPT detector.
🔒  Safe & secureYour data is encrypted and not stored.
👨‍💻  API accessAPI access to the GPT Detector on request.
What is Writefull?
At Writefull, we develop AI tools to write and revise academic texts. You can use these to copy edit, generate abstracts, paraphrase texts, make your sentences academic, and more. Writefull for Word and for Overleaf are available from our website (click the 'Get Writefull' button at the top of this page).
How do I use the GPT Detector?
Enter your text into the text box and click 'Check'. You'll instantly get your verdict! It gives a percentage of likelihood that a text was written by GPT. This can be GPT-3, GPT-4, or ChatGPT.
Is the GPT Detector free to use?
Yes, you can use it for free, with a daily quota that we set to avoid abuse.
At what percentage do I know a text has been plagiarized using GPT-3, GPT-4 or ChatGPT?
The higher the percentage, the more likely, but there is no absolute threshold. The more creative the language used in a GPT-plagiarized text, the more difficult it is to recognize the 'voice' of GPT-3, GPT-4, or ChatGPT in it. And a GPT-text's language creativity depends on many things, like the parameters set and the prompt entered. For example, ChatGPT can be prompted to use long or short sentences, a confident or careful tone, and formal or informal vocabulary.
Do you have an API of the GPT Detector?
Yes, you can also use our API to automatically detect content generated by GPT-3, GPT-4 or ChatGPT. Contact us at for more information.
Can I use ChatGPT, GPT-3, or GPT-4 to write or proofread my academic papers
All academic texts, whether essays or journal papers, should be written by yourself. Using GPT-3, GPT-4, or ChatGPT to write your entire text for you is considered AI-assisted plagiarism (sometimes coined 'AIgiarism'). The general consensus is that it's fine to use an AI tool like ChatGPT or Writefull to proofread, edit, or tweak your text, but not to write it for you.
Does the GPT Detector also detect text generated by GPT-4.5 or GPT-5?
GPT-4.5 and GPT-5 are still in development, and there are no release dates yet. Once GPT-4.5 or GPT-5 has been released, we will update Writefull's GPT Detector so that it also reliably detects texts by those.
Do you have more AI tools to check texts?
Sure! Download Writefull for Word or for Overleaf to instantly see how well-written a text is, and correct it using the best AI feedback. Several independent analyses by publishers and copyeditors have shown that Writefull outperforms all other AI proofreading tools - so why not give it a try? (It's free, too.)