Considerations for Follow-on and Foreign Filing

Once your US application has been on file for six to nine months, it's time to start thinking about the next step. You may want or need to have follow-up applications filed before the first anniversary of your US filing date. If you miss this deadline, your options for further filings may be severely limited, if not eliminated entirely. If you originally filed as a provisional application, you're going to need to file a follow-on application before the first anniversary of its filing, or you will lose the benefit of the provisional application filing date entirely. 

Important Note: This page deals with the options facing an owner of an "original" patent application as the one-year anniversary of the filing date approaches. By "original" we mean the first application disclosing an invention, which might be a provisional application or a Utility Application. The one-year filing deadline runs from the filing date of the earliest application in a family of applications, so if you have already filed a Utility Application claiming the benefit of one or more provisional applications, it is the filing date of the earliest ("original") provisional application which will start the one-year clock running. If this seems confusing, it might be helpful to review our Patent Timeline and Patent Q&A pages, and we have a Patent Glossary if some of the terms in this page are unfamiliar. . 

If your original application was a provisional application

A provisional application acts, in effect, to reserve a filing date for a period of one year, after which it become abandoned. If you are planning to continue with the prosecution of the application, within one year of the filing date of the provisional application you must file a "follow-on" application, which can be either (a) a U.S. utility patent application claiming the benefit of the provisional application, or (b) an international stage application through the Patent Cooperation Treaty (PCT) claiming priority from the provisional application. If you do file one of these applications before the deadline, the filing date of the provisional application will be the effective filing date of the newly-filed utility or PCT application. If you do not file by that time, you will lose the benefit of the provisional application filing date.

It is very common that a follow-on application will include more details than the provisional application upon which it is based. Also, a utility or PCT application requires claims defining the scope of the invention on which you are requesting patent protection. Please contact us at soon as possible if you are planning to file a utility patent application based on your provisional, so that we may discuss the changes, if any, which will need to be made to the provisional application to turn it into a finished utility application. Once we have that information, we can give you an estimate of what the cost will be.

See our page on provisional applications and our page on the PCT for more information. We also have a Patent Budget Estimator with information on filing utility patent applications.  

Seeking patent protection in other countries

Your US patent application, when and if it issues as a patent, will allow you to stop others from making, using or selling the claimed invention in the United States of America, only. If you will want protection in any other country, it is necessary to get separate patent coverage in each country in addition to your US patent. If you would like to file patent applications in foreign countries based on your US patent application, with the US filing date of your "original" application being effective as the filing date in these foreign countries (the "priority date"), you must do so before one year from your earliest US filing date.

We can assist you in foreign filing, through a network of foreign agents with whom we work. Be forewarned - international patenting is not for the faint of heart or weak of pocketbook. Your decision in which countries (if any) you will want protection will depend on the nature of your invention and industry - where do you think you will be most likely to encounter markets, competitors or potential licensees?

There is no such thing as an "international patent", as such, although there are a few regional patents covering some countries - EPO for the European Union countries (plus some others), ARIPO and OAPI in Africa, and the Eurasian Patent covering Russia and some of the former Soviet republics. Other than these regional systems, you will need to file for a patent in each country in which you will want patent protection.

It is not really possible to accurately estimate the total cost of foreign filing in a generalized way, since it varies so widely depending on what countries are chosen, what method of filing is pursued, the fees of foreign patent attorneys in each country, exchange rates, translations, etc. Also, many of the costs are related to the details of your patent application (number and arrangement of claims, number of pages, and so on).

A budget of $10,000-$15,000 would be realistic for a single foreign country (or region such as the EPO), other than Canada. Please note that while we do not mark up foreign agents' bills - you are responsible for paying their charges as they bill them - we do charge a fee of $975 per country at the time of filing to cover our time spent corresponding with foreign agents, assembling documents, docketing deadlines and so on. Many countries have extra fees to request examination, and most have annual fees (annuities or maintenance fees) payable during the pendency of the application and/or after the patent issues. Expect additional costs later on for analyzing and responding to foreign office actions, docketing and paying maintenance fees (annuities), etc.

It has been our experience that the majority of our clients who do any foreign filing will file in one or more of three places: Canada, the European Patent Office (EPO), or Japan.

Canada: Canadian practice is straightforward, and correspondence can be conducted in English, all of which makes Canada a real bargain. Given the close relationship of the Canadian and US economies, we recommend Canadian filing even if you do not intend to pursue any other foreign rights. A Canadian application corresponding to a US application can be filed for about $1,500 - requesting examination, which doesn't have to be done at the time of filing, would add about $1,000. 

Europe: If you are interested in filing in three or more countries which are members of the European Patent Convention, significant savings can be achieved by filing an EU patent application through the European Patent Office (EPO). The application is filed in English, and we work through an excellent agent in London so there are no language problems in the process. The cost for filing and requesting examination of your application in the EPO would be approximately $9,000. Once the EPO patent issues, the claims (only) will have to be translated into French and German. The patent then must be registered in those European countries in which you will want protection, and will need to be translated into the appropriate languages for those countries. Additional costs of $3,000-5,000 per country may be expected at that time (translation costs are a major part of this), and annual maintenance fees (annuities) are due in the EPO until the patent issues, then in each of the individual countries after registration. For the countries which could be covered by an EPO application, look for the code <EPO> on our list of PCT members

Japan: Practice in the Japanese Patent Office (JPO) is very different than in the US, Canada or EPO. If nothing else, everything must be translated into Japanese, which is not inexpensive, and the JPO is very picky as to claim structure (they prefer fewer, narrower claims than in other countries). The cost of filing and requesting examination on your application would be about $7,500. You can expect that the cost of dealing with Examiner's Actions in Japan will be somewhat higher than in the US as well, both because of differences in procedure and the cost of translations. Annuities are a major component of cost in Japan - over the life of a patent, these will total over $20,000.

If you are interested in filing in some other country, we have a computer program which does a very good job of estimating costs in most countries around the world. Please contact us for details on your countries of interest.

An alternative route: the Patent Cooperation Treaty (PCT)

If you know you will want some foreign protection, but are not sure where, or you want to delay the major costs of foreign prosecution until you have some idea of how the US patent application will fare or until you have established a market here or found licensees overseas, consider the Patent Cooperation Treaty (PCT)

You can file a PCT application in the US Patent and Trademark Office, which delays your deadline for foreign filing up to 30 months from the date of your US patent application (31 months, in some countries). (Important Note: this only applies if the patent owner or at least one inventor is a US citizen or resident - if the owner is not a US citizen or resident and none of the inventors are US citizens or residents, the PCT application will need to be filed elsewhere, if it can be filed at all)

New countries join the PCT each year - for the most up-to-date list see our list of PCT members.  Most industrialized countries are members of the PCT, but in case you have a particular country in mind, we also have a list of countries not in the PCT  - for example, Taiwan is not a PCT member. 

After the expiration of the 30 months (or more) you will need to file national (or regional) patents in whatever countries in which you decide to pursue protection. The cost to file a PCT application is approximately $4,000, mostly in government fees. One of the biggest parts of this is the search fee. The most expensive route is to have the PCT search done by the the USPTO or European Patent Office (EPO). Using the Korean IP Office (KIPO) for the International Search will save over $1,000 in fees. 

You can find more information on the PCT at:


Because we must work through patent attorneys in each country, and often must forward fees on short notice, we require that all foreign application fees be paid in advance, and will request additional advances as prosecution proceeds. Most foreign agents expect to be paid in their home currencies, but our clients pay us in US Dollars. This will always be a problem because exchange rates will change between the time the agent's bill is prepared and the time the bill is paid. It is your responsibility to pay the agent the full amount due in whatever currency they request - we cannot insure against unfavorable shifts in exchange rate. Therefore, if a foreign agent sends an invoice in other than US Dollars, we will add 20% to the equivalent US Dollar amount of the agent's bill at the exchange rate on the day it is received, as an exchange rate buffer to allow for shifts in exchange rates. Once the fee is actually paid to the foreign agent, any overpayment will be applied to other outstanding fees, or if there are none, refunded or held against future fees at your option.


The one-year deadline for follow-on filings is non-extendable. If your follow-on filing will be in a foreign country, you need to allow extra time - a month or more by preference - to allow foreign agents to prepare the needed translations and make the filings. If you wait until the literal last minute, it will cost much more for rush service. Remember that the deadline is measured by the local time in the office in which you want to file - in several cases our clients have waited so long that they discovered that the filing deadline had already passed in Japan or Europe, and they lost their foreign patent rights.  

There's another important factor to remember: US law requires that you obtain a Foreign Filing License before you file an application in a foreign country. This is normally issued as part of the filing receipt, which can take quite some while to arrive back from the USPTO. This isn't an issue if you file through the PCT, since international stage PCT filings (for US inventors) are filed in the USPTO. If you decide to pursue direct foreign filing in individual countries, you will need to leave sufficient time after your US utility filing for us to get the license, if any significant amount of material has been added to the provisional filing. Please notify us as soon as possible so that we have sufficient time to process the application, and, if necessary, obtain translations for those countries. 

Please contact us  if you have any questions on your foreign filing options. 

Last updated: Tue, 16 Feb 2021