Is the patent link to the patent valid?

Has it been granted?

For which countries does the protection apply?

Are there other patents associated wth it?

How do I know all this?

(This question is designed as a meta question to answer all those questions appearing around here asking one or more of these questions for a special patent once and for all)



The life cycle of a patent starts with the application. The inventor files this application with a patent office, for example the USPTO (US Patent and Trademark Office). This grants them the right to say "patent pending", but no enforceable protection rights. Everyone can file a patent application, containing basically everything (apart from obviously illegal texts submitted as patent applications, insults maybe or applications that don't meet the formal requirements as to how a patent application has to be submitted).

A recent patent application gets an publication number that starts with a country code (US, EP, ...), followed by a year (e.g. 2007) and a number. (Note: This is true for the US and Europe and many other countries, but may not be true for all countries, keep reading). This is the number you normaly find for applications when looking on the internet. If you somehow got the application number and can't find it on google, try the "Public Pair" (http://portal.uspto.gov/pair/PublicPair) for US applications or the national patent office (or espacenet for Europe) for other applications to find the publication number.

A recent patent application publication is followed by the 'kind code' A or A1 or A2 or ...

Patent kind codes and publication numbers have changed in the past.

Only because a patent has been published as an application (not every patent is), this does not mean it hasn't been granted:


After the application there may (or may not!) come the grant of the patent. This means that the claims in the new publication of the granted patent are enforceable rights. Infringing them can get you in legal trouble. Those claims are regularly not the same as those in the application. It is normal to include very braod claims in the application and then iteratively narrow them during the examination. For the patent (application) holder this has the advantage that third parties don't yet know what the final claims will be, so they have to fear them, if they are broad at the beginning. A thorough analysis can get you a hint at how much might be patentable, but in the end, if you infringe the claims of an application and that part stays in the granted claims, you are liable for the time were the patent was an application too.

This is indicated by a new patent number (they are awarded counting up, recent grants in the US start with a 9) and a 'B' kind code. **The application number does not disappear and can still be found! **

How to tell what it is

Google patents shows a summary on the right of the page where you can find other numbers the patent document has been published as. If you find a granted patent number there, the patent has been granted. Click on it to find the date of grant. If there is non, you should make sure google is not mistaken. Click on the espacenet link and check for the "published as" links there again.

And thats it. It is that simple. However ...

The thing with the fees and

Not every granted patent still is enforceable. If the fees aren't paid or the patent is invalidated, the rights vanish. And nowadays the normal patent term is 20 yrs. (https://patents.stackexchange.com/a/17059/18033 this answer provides a way to figure out if the patent has lapsed).

In which countries and are there associated patents?

From google patents click on the espacenet link and then on family members. Those are the associated patents. They have a country code (and it says the country if you click on it). Only countries with a granted patent in it are part of the protection.

European and PCT (international) patent applications have a national phase where they enter the designated countries, European patents enter when granted, PCT applications never get granted on the international level, they enter national phase as applications. So if you cannot find a national patent for the PCT application, it has no protection in that country (or you failed).

Countries for a European granted patent can be looked up on the legals tab of espacenet. This however relies on data from the national patent offices, so if in doud, search for the national counterpart.

An example


Number: US20100289665 A1 This is an application.

Google shows us:

https://www.google.com/patents/US8531308?hl=en (The granted version)



(Espacenet link)

Family members:


(Itself and the PCT application (WO....))

We see, at this moment, this patent is only enforceable in the US.



A PCT application is an application filed under the Patent Cooperation Treaty, which is an international treaty with 150ish members. A key characteristic of a PCT application is that its patent number will begin with PCT (for an application number, such as PCT/US2016/012345) or WO (for a publication number, such as WO 2016/123456 A1).

The purpose of the PCT system is to provide the applicant with additional time in which to select their final countries for protection. Without a PCT application, the applicant must decide which foreign countries they wish to file Convention applications in before 12 months after filing the first priority document. With the PCT system, this is extended to 30–31 months from the filing date of the first priority document (and occasionally longer for certain countries). Some might therefore consider a PCT application to be nothing more than an expensive extension of time.


A PCT application must be filed before the end of 12 months after the earliest priority document was filed. For example, if a priority document was filed on 1 Jan 2010, the PCT application must be filed by 1 Jan 2011 in order to validly claim priority. It is also possible for a PCT application to not have any priority claim, though this is relatively rare.

At the 30–31 month stage, the applicant must "enter national phase" by filing an application directly in each country in which the application wishes to pursue protection. These applications are deemed to have been filed (for the purposes of prior art) at the time that the original priority document was filed. At this point, the PCT application has no rights outstanding, and effectively lapses.

Between filing and national phase, the PCT application will be searched by an International Searching Authority (ISA), and sometimes subsequently examined by an International Preliminary Examining Authority (IPEA). These are national patent offices working in the capacity of ISAs and IPEAs. The applicant need not respond to these a international search report (ISR) provided by the ISA or an international preliminary report on patentability (IPRP) provided by the IPEA, so a negative finding by the ISA or IPEA will not hamper the application. But the results may be used by a national patent offices during the national phase.

An example timeline of a PCT application is:

1 Apr 2015: US provisional application filed (P1). 1 Apr 2016: PCT application filed (WO1) claiming priority to P1 (before 12 months from P1's filing date). 1 Oct 2016: WO1 publishes (18 months from P1's filing date), and its details are now made public on Patentscope. 1 Oct 2017: WO1 enters national phase (30 months from P1's filing date) in selected countries, so national applications are filed in Europe, China and Japan claiming priority to P1.

Finding information about a PCT

WIPO administers the PCT system. They provide [Patentscope]( https://patentscope.wipo.int/search/en/search.jsf) which allows you to check the status and documents related to a PCT application.

Notably, it also provides a listing of countries in which national phase has been entered. However, this is not always accurate, so further investigation would be prudent in important cases.

What rights does a PCT application provide?

PCT applications never directly result in a granted patent, and therefore do not directly provide rights of enforcement anywhere in the world. They effectively just act as a placeholder before the applicant needs to enter the national phase.

Only the applications which are filed as part of entering national phase can result in a granted patent which provides rights of enforcement.

Therefore, if you are considering the infringement risk presented by a PCT application, you should look at what applications have been filed during the national phase, and consider their status, rather than the status of the PCT application.

  • A good canonical answer. I just have a few minor suggestions: (1) USPTO stands for United States Patent and Trademark Office. (2) It's fine to pursue protection for illegal things (per TRIPS art 27(2), which basically every country implements). (3) An application number does not start with a year in the US—only the publication number does. Similarly, the A kind code applies to the publication only, not the application. – Maca Jan 30 '17 at 23:14
  • A very good start. Once you make the corrections as suggested by Maca, I'll be happy to up vote the answer. – Eric S Jan 31 '17 at 2:32
  • Thanks, writing such a long answer had to go wrong somewhere, I'm glad it was only 'minor' stuff. I clarified what I meant with illegal, I wasn't talking about the invention but the patent application itself, e.g. filling an application form with swastikas here in Germany or something thelike. But I see that wasn't clear. – DonQuiKong Jan 31 '17 at 7:51
  • @DonQuiKong The one thing I think might improve this answer is some discussion pointing out that the claims may change considerably between an application and a granted patent. Many applications have excessively broad claims that freak out patent newbies. Those almost always get narrowed before grant. – Eric S Jan 31 '17 at 21:52
  • Good idea, included some more informations on the claims. – DonQuiKong Feb 1 '17 at 17:37

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