How to calculate the duration of patent right?

According to relevant laws, the first day (starting date) of the term is not included in the term. If calculated in years or months, the expiration date shall be the corresponding day of the last month; If there is no corresponding day in the current month, the last day of the current month shall be the due date. For example, the filing date of an application for a patent for invention is1June 65438+ 1 day, and the validity period of its substantive examination request should be 200 1 day, not 20065438. Another example is the notices of 1999, 12 and 16 issued by the Patent Office, which should have been received by 1999, 12 and 3 1. If the notice stipulates that the time limit is two months, the expiration date of the time limit shall be February 29, 2000. If the due date is a legal holiday, the first working day after the holiday shall be the due date. The relevant laws clearly stipulate the longest protection period of patent rights. During this protection period, it is not excluded that the patent right will be terminated before the expiration for some reasons. Of course, if the statutory maximum protection period has been reached, the patent right will definitely be terminated, which is understandable. Because, after the longest protection period, you can't apply for an extension.