GPTZero is a free AI detector tool that can be used to check whether a document was written by a large language model. It is trained on a large, diverse corpus of human-written and AI-generated text, and it is the most accurate AI detector across use-cases. GPTZero is useful for a variety of purposes, including educators, employers, publishers, and researchers. To use GPTZero, simply paste the text that you want to check into the text box and click the "Check" button. GPTZero will then analyze the text and give you a score that indicates how likely it is to have been generated by AI. A score above 50% means that the text is likely to have been generated by AI, while a score below 50% means that the text is likely to have been written by a human.