Hi, I'm John Rizvi, the patent Professor, I'm often asked what happens to a patent after 20 years. So the duration of a patent is 20 years. And the US patent is a monopoly that you can use to prevent somebody else from making using selling or importing the idea in the United States. This monopoly lasts for 20 years after your filing date. And once the 20 years are over, you cannot prevent anyone from using your idea. In fact, after the 20 years, your idea is considered dedicated to the public. And that means that anybody else can use your idea without owing any licensing or royalty payments to you or getting your permission. But it also means that nobody else can file a patent on your idea either, because it's part of the public domain. The only way they can file another patent is if they improve your idea and come up with some new novel and non obvious change. If you have other questions about patenting. Give me a call.