International patent applications

A ‘PCT patent’ or ‘PCT application’ is an international patent application covering most countries. PCT applications are filed in accordance with the Patent Cooperation Treaty (PCT).


What is the Patent Cooperation Treaty?

The PCT is an international agreement by which most countries each agree to treat a single international patent application as a local national patent application.


Countries covered by PCT applications

PCT applications cover 157 countries:

Source: World Intellectual Property Organization


The following countries are NOT covered:

Afghanistan, Andorra, Argentina, Aruba, Bahamas, Bangladesh, Bhutan, Bolivia, Burundi, Democratic Republic of the Congo, Eritrea, Ethiopia, Fiji, Guyana, Haiti, Holy See, Kiribati, Lebanon, Maldives, Marshall Islands, Micronesia, Myanmar, Nauru, Nepal, Pakistan, Palau, Paraguay, Solomon Islands, Somalia, South Sudan, Suriname, Taiwan, Timor-Leste, Tonga, Tuvalu, Uruguay, Vanuatu, Venezuela and Yemen.

If these countries are of interest, separate national patent applications can be filed alongside the PCT application.


No international patents

Strictly speaking, there is no such thing as an international patent. PCT applications are temporary and serve as stepping stones to multiple patents in multiple countries.


How long does a PCT application last?

PCT applications last until about two-and-a-half years into the patenting process. The timing varies from country to country. For most countries it is either 30 or 31 months.
This two-and-a-half-year period and other key dates discussed below are calculated from the start of the patent process, which might be the filing of a stand-alone PCT application or the filing of a provisional patent application:

  • If the PCT application is filed as a stand-alone application, the key dates are calculated from the date of filing the PCT application.
  • If the PCT application is linked to one or more earlier patent applications, the key dates are calculated from the filing date of the earliest patent application as in the flow chart below.

How to patent flow chart


Pending PCT application

Shortly after filing the PCT application, an International Search Report will issue. This provides an indication of the patentability of the invention. In the following months, you may choose to file a response to the report. This stage is called the ‘international phase’.


The end of the PCT application

At the end of the two-and-a-half years, it’s time to select and pay for the individual countries (or regions) of interest. This step is called ‘entering the national phase’.

There are regional patent systems in Europe, Africa (OAPI and ARIPO), the Arabian Peninsula and Eurasia but, for the most part, countries must be selected individually.

Selecting PCT countries


After the PCT application

Examination in each country or region typically commences a year or two after entering the national phase. The timing varies significantly from application to application and country to country. Feedback from US patent examiners can arrive with six months, whereas it could be several or more years before feedback arrives from Brazil.


PCT patent infringement

PCT applications cannot be directly enforced. If a pending PCT application is infringed, the national phase can be brought forward and accelerated in the relevant countries and then the separate national patents can be enforced. In the meantime, you may put the infringer on notice or threaten the infringer, depending on your confidence in the strength of your position.


PCT patent publication

PCT applications are published at the 18-month mark. This enables competitors to see the detail of the invention. PCT publications typically included text and figures. The ‘claims’ are key sentences towards the end of the text that define the patent coverage. The remainder of the text and figures describe and illustrate preferred versions of the invention. More on How to read a patent.

If you don’t want to continue patenting, publication can be avoided by withdrawing the PCT application well in advance of the 18-month date.


PCT patent search

After they are published at the 18-month mark, PCT applications appear in the World Intellectual Property Organization’s (WIPO’s) Patentscope database and can also be located in the European Patent Office’s (EPO’s) Espacenet database and in Google Patents.

PCT applications that have not yet been published do not appear in any publicly available databases. When searching for pre-existing patent rights that might cover a proposed product or process, there is always the risk of missing a relevant PCT application that is not published until after the search.


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