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)

1 Answer 1



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 is published, usually 18 months after filing, and 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 publication number is the number you normally find for applications when looking on the internet but, at least in the U.S., is not the actual application number which, in the U.S. is in the form 16/035,349. If you somehow got the actual application number and can't find it on google, try the "Public Pair" for US applications or the national patent office (or Espacenet for Europe and elsewhere) for other applications to find the publication number. By the way, Public PAIR has an unforgiving user interface.

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.

Just because a patent application has been published (not every patent is), does not mean it has or 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 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 broad claims in the application and then iteratively narrow them during the examination so the granted claims are likely not to be the same as the claims in the publication. A thorough analysis can get you a hint at how much of the original might be patentable, but in the end, if you infringe the claims of an application and that claims stays in the granted claims, you could be liable for the time were the patent was a published application too. At least in the U.S. this requires you to have had notice of the publication. These rights are, confusingly, called provisional rights and have zero to do with provisional applications.

A grant is indicated by a new patent number (they are awarded counting up, recent grants in the US start with a 10) and a 'B' kind code.

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 none, you should make sure google is not mistaken. Click on the Espacenet link and check for the "published as" links there again.

And that's it. It is that simple. However ...

The thing with the fees and

Not every granted patent still is enforceable. If the renewal/maintenance fees aren't paid or the patent is invalidated, the rights vanish. And nowadays the normal patent term is 20 yrs from filing. (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 and/or published application. 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.

PCT (international) patent applications are a single "physical" application that is 150+ applications in as many places. The PCT process causes preliminary searches to be performed but does not, itself, ever result in a patent. To do that one needs to enter the "national stage" in one or more of the 150+ designated countries. This keeps the original application alive past the 30/31 month point. And then work with the examiners in each office according to the laws and procedures of each specific office.

The European Patent Office is a regional patent office. Like a countries office, it is one of the 150+ places one can enter the national stage (but would be called entering the regional stage) of a PCT application. Alternatively it is also possible to just apply to the EPO as if it were a country with no use of the PCT process.

If you get a patent grant from the EPO, that currently provides no actual infringement protection itself. At some point there will be an integrated European patent court system but now an EPO grant must be validated in one or more EPC locations to have any teeth. This is a purely bureaucratic process with no review before an EPO patent spawns a UK, DE, etc. enforceable patent.

They are enforced in courts of the issuing country just as if they have been granted directly by a UK, DE, etc. application. One twist is that if the UK patent is invalidated there, there is no automatic effect on the DE patent. On the other hand if the EPO renewal fees are not paid all of the spawned patents go away!

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 doubt, 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, an enforceable patent was only issued in the U.S.



A PCT application is an application filed under the Patent Cooperation Treaty, which is an international treaty with 150ish members, as mentioned above. 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 Paris 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 but it also provides a preliminary search and has other benifits.


Under Paris, 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 continuing the application 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. After the 30/31 month point, the PCT application has no rights outstanding, and effectively lapses.

Between filing and any national phase(s), the PCT application will be searched by an International Searching Authority (ISA), and sometimes subsequently examined by an International Preliminary Examining Authority (IPEA) - usually the same patent office as selected by the applicant. 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 autocratically 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 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 can be seen as a placeholder before the applicant needs to enter the national phase but have other properties.

Only the applications which are extended into a national/regional phase can result in a granted patent which provides rights of enforcement. Entering a national/regional stage requires a fee determined by each location

Therefore, if you are considering the infringement risk presented by an other's PCT application, you should look at what applications have entered the national phase, and consider their status, rather than the status of the PCT application.

  • 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.
    – user18033
    Commented Jan 31, 2017 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
    Commented Jan 31, 2017 at 21:52
  • Good idea, included some more informations on the claims.
    – user18033
    Commented Feb 1, 2017 at 17:37
  • @DonQuiKong Do you think you should add a little content distinguishing between a provisional and non-provisional application? I do think a lot of entrepreneurs I deal with are fuzzy on the difference.
    – Eric S
    Commented Feb 11, 2017 at 17:31
  • I don't know as much about that, maybe you want to make it a different question, we could link it. Or edit it in yourself.
    – user18033
    Commented Feb 11, 2017 at 18:16

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