The Paris Convention versus the PCT

We briefly discussed the difference between PCT and Paris Convention filings here and here.  Let’s go into a little more detail.

The Paris Convention

As we discussed, the Paris Convention is an international treaty that allows applicants to file a first application in their home country. That application is referred to as a priority document or filing, and the date it is filed is called the priority date.

The priority filing starts a 12-month period within which a further application called a Paris Convention application (or a direct application claiming priority) can be filed elsewhere, claiming Paris Convention priority back to the priority date. To the extent that the content of the Paris Convention application is disclosed in the earlier priority document, it will be backdated to the priority date.

The advantages of using the Paris Convention are well known to those familiar with the patent process. The 12-month convention period lets the applicant seek funding, perform market research and turn an idea into a commercial product. All of these can be done following a single filing without risking a loss of rights in other countries.

If the Paris Convention didn’t exist, applicants would need to coordinate simultaneous filing in all countries that are of potential interest at the very start of the process. This would be complicated and costly, bearing in mind the need for translations in many countries.


Like the Paris Convention, the Patent Cooperation Treaty (PCT) is an international treaty. Also like the Paris Convention, it allows the filing of a single application in the applicant’s home country while preserving rights in other countries.

The difference is that the PCT is expressly equivalent to filing a patent application in each designated PCT country. The PCT procedure also includes an International Search Report, which may assist the applicant in determining what prior art the application might face before the individual national patent offices. An optional international examination procedure allows the presentation of further amendments and arguments, just like examination in front of the national patent offices.

30 months (31 months in some countries) after the priority date of the PCT application (or of the PCT application itself if no Paris Convention priority is claimed), an application must enter the national phase in each country or region of interest. For example, a PCT applicant interested in Europe, Japan and China would ensure that the Japanese and Chinese applications were filed within 30 months of the priority date, and that the European application was filed within 31 months of the priority date. The application then proceeds as a normal patent application in each country or region for which the national phase was entered.

So in essence, the PCT is a time-buying exercise. You file a single application with fairly high fees, which reserves your rights for about 2.5 years from the priority date. This is considerably longer than the 12 months offered by the Paris Convention.

You’ll also note that a PCT application can claim Paris Convention priority to an earlier-filed application.

PCT or Direct Paris Convention?

In our previous article, we discussed why an applicant might choose the PCT or the Paris Convention. Here’s the table again:

PCT paris chart

While the PCT has advantages, it does have relatively high up-front fees. Applicants with a tight budget and an interest in only a limited number of countries may therefore choose to file direct Paris Convention applications, rather than a PCT application. Especially if translations are not involved, you may be able to file three or even more Paris Convention applications for the cost of a PCT application.

In most countries, PCT applications are treated just like ordinary direct filings when it comes to examination. They’re put in the queue and examined in some sort of order. The PCT delays entry to this queue by up to 18 months or more. That may not be helpful if you need or want a quick grant. There are several reasons why a quick grant might be of interest. Perhaps you’re in an industry with lots of copying, and you want a granted patent to use against infringers. Maybe successful licensing or assignment of the invention hinges on grant of a patent. In such cases, direct filings will typically speed progress of an application towards grant.

Direct Paris Convention filings are also required for non-PCT countries. For example, Taiwan, Argentina and Pakistan are not PCT signatories, but are often assumed to be. Several Middle-Eastern countries (eg, Jordan, Kuwait and Saudi Arabia) and African countries (eg, Eritrea, Ethiopia) are also not members. Some industries (eg, mining) require patent protection in such destinations, which can only be achieved by direct filing.

Finally, “PCT or direct Paris Convention?” isn’t an “either-or” question. Applicants can mix and match their direct and PCT filings to take into account their overall commercial strategy. For example, an applicant could choose to file a PCT, along with a simultaneous direct filing into one or more commercially important destinations such as the USA. This approach gives maximum flexibility – the PCT keeps the invention’s rights available in a large number of countries, while prosecution and grant of the direct-filed US application can be expedited for commercial reasons.

Why might delay (and therefore the PCT) be preferred? Maybe you’re not confident that the invention will lead to strong protection. Many applicants feel that a pending application is worth having, even if it seems likely that only a very narrow – or even no – patent will ultimately grant from it. In such a situation, expediting the process will lead to faster refusal, which means the application will be pending for a shorter time.

Filing strategies can be complex, and you should consult your patent attorney before making any decisions. Hopefully these comments will give you some ideas for discussion.

Feel free to contribute other reasons for choosing the PCT or direct Paris Convention filings.


If you’re looking for more information on these processes, please consult these resources:

  • PCT national stage entry interactive guide – information on PCT national stage entry and country-specific filing requirements.
  • – create a free account to get an instant quote for PCT national stage entry or direct (Paris Convention) filing.
  • inovia webinars – sign up for an upcoming International Patenting Strategies “101” program.

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