Plagiarism Checker

A plagiarism checker scans your text and compares it against content that already exists, typically against a wide database of online sources including academic papers and articles. It shows how much of the inputted text is original, and highlights any overlaps with existing sources. Plagiarism is taking someone else’s words and presenting them as your own without crediting them, and a plagiarism detector helps educators and students to avoid doing this accidentally.

GPTZero’s plagiarism checker is built for accuracy and transparency. We are able to detect plagiarism from over 100M scholarly articles, research papers, websites, and books with confidence. Presenting AI-generated text as your own can also count as plagiarism in many cases. In our tests and third party studies, our AI detector’s accuracy is over 99% in identifying pure AI-generated content.

Yes. GPTZero offers a free plan that covers up to 10,000 words per month. If you need more, you can upgrade to a paid subscription for higher limits.

It’s very simple: either paste the text into the tool or upload a file. The plagiarism checker scans it against a database of sources and quickly returns a similarity score, showing the percentage of overlap with existing content.

GPTZero’s plagiarism checker is the best in terms of accuracy and transparency. We don’t just give you a score: we show you which specific parts of the text might be flagged and link you to the original source. This is what makes GPTZero especially useful for students and teachers who want guidance on how to improve their work.

It can be. If you use an AI tool to create text and then present it as entirely your own, that can be considered “AI plagiarism.” The best practice is to be transparent, and learn to cite AI as a source, making sure your final work is a reflection of your own original thinking.

The similarity score shows how much of your text matches existing sources. Our software compares vocabulary, sentence structure and phrasing, and alerts you when passages sound too much like other sources.

The simplest way to avoid plagiarism is to be transparent, and always give credit when you have used someone else's words or ideas. Add citations when you use someone else’s research and use quotation marks if you’re copying a phrase directly. Running your work through a plagiarism detector is also a good idea as it can ensure your writing is truly original.