How is the patent protection fee calculated? What is the calculation method of this fee?

China's laws have the following provisions on patent protection fees: there is no protection fee for invention patents, but an annual fee is paid according to the regulations. In the first three years, the State Patent Office reduced or exempted the annual patent fee applied for, which was 85% of the original application, but it should be submitted when applying again. In the future, the annual fee will be different according to the delineation. Although the annual fee of 4-20 years has not been reduced, you can still apply for subsidies from the Patent Office after getting the certificate. As long as the annual fee is paid, the patent right is protected. The annual fee for individual application for invention patent is as follows:1-3:13510-/2: 4000 4-6:13-15: 6000 7-9: 2000.