(1) Log in to the official website of the European Patent Office (https://www.epo.org/) and click "European Patent Register" in "Legal information" under the "Searching for patents" entry at the top of the homepage.

(2) Click "Open" on this page to enter the patent query page. On this web page, you can check the legal status and annual fee information of patents applied through the European Patent Office. For patents not applied through the European Patent Office, you need to enter the official website of the national intellectual property office to check.

(3) After entering the patent search page, enter the patent number/application number in "Search term(s)" and click "Search" to query the legal status and paid information of the patent. If the patent has been authorized, you need to check the legal status and annual fee information in each effective country. After querying this patent, click "Legal status" on the left side of the page to query the patent information of each country.

European patent maintenance fees