When to apply for European patent
In a general way, when a European Patent application is made, it will
claim priority from an earlier patent application for the same invention,
for example an earlier German patent application.
In order to claim priority, the European patent application must be filed no later than 12 months after the earlier application. The claim to priority must be made at the time of filing the application for the European Patent.
Claiming priority means that for some purposes your European Patent application
is back-dated to the date of the earlier patent application. In particular,
the patentability of your invention is judged against the public knowledge
at the date on which the earlier application was filed, insofar as the
earlier application contains sufficient information about the invention.
This date is known as the priority date of the European Patent application.
For example, you may wish to file initially a relatively cheap UK patent
application at an early stage in the development of your invention, in
order to establish a priority date. Following this first filing, you have
a year to develop your invention further, and to work out whether it is
commercially viable, before you have to decide whether to invest in a
It is possible to file an application for a European Patent without claiming any priority. It is also possible to make a European Patent application via an international application under the Patent Co-operation Treaty (PCT).
In the remainder of this briefing, it is assumed that you are filing a European Patent application claiming priority from an earlier patent application filed 12 months previously.