The European patent will produce in each of the designated states the same effects as a national patent. The applicant however has the opportunity of designating, from among all the member states, those that are of interest. Use of this possibility is often made to limit the costs for translations and for the annual fees that are due in the different states.
If four or more states are to be designated, it is more advantageous to file a European application rather than to take the national route in each state. Many applicants chose to file a European application even if only two or three states are to be designated, in order to secure an identical patent in the different states.