When does a Patent Expire?

Mary McMahon
Mary McMahon

The date at which a patent will expire is generally 20 years from the date of filing. However, there are some nuances to the situation which can complicate matters, and patent expiration dates also vary from nation to nation, and may depend on when the patent was filed and issued. When preparing to file a patent, it is a good idea to make sure that one is familiar with the laws which surround patent expiration, to confirm that the application will be valid and to see how long it will be valid for.

Patent expiration dates are a major factor in the pharmaceutical industry.
Patent expiration dates are a major factor in the pharmaceutical industry.

Many patent agencies set up a patient expiration that kicks in 20 years after filing. In the United States, if a patent was filed after 8 June 1995, the 20 year period holds true. However, if someone filed for and received a patent before 8 June 1995, the expiration date may be 17 years from the date of issue, or 20 years from the date of filing, depending on which date is further in the future and when the patent was received.

When filing a patent, people are expected to research to confirm that the patent is original and that it is not infringing on an older patent. Once a patent expires, infringement is no longer an issue, because the patent holder does not hold the rights to the patent any more. When a patent is examined by a patent examiner, she or he will also research to confirm that the patent meets the standards set by the government for the issuance of patents.

In the United States, people who take out a utility patent must pay maintenance fees on the patent. If these fees are not paid, the patent will expire even if the 20 year period has not yet elapsed. The procedures for paying maintenance fees are fairly simple, and people have several options which they can use to pay fees, making it easy to keep up and ensure that a patent will not lapse.

In some cases, the expiration dates of patents have been extended by special arrangement. This is most commonly seen with pharmaceutical patents, under the argument that research and development are so costly that the company needs more time under an exclusive patent, or under the argument that a use for a medication is new, allowing the patent to be extended under a new patent application. This practice has been criticized by some advocates who are concerned about the high cost of patented medications.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


With so many new products being developed these day, I think that a career as a patent attorney would be a good choice.

Especially, in the fields of medicine and technology, a lot of similar drugs and technology products may apply for patents. It may be difficult to tell how similar the products are, and which patent applications are clearly original. If companies or innovators contest another's right to a patent, a patent lawyer steps in.


I'm not so sure I agree with the practice of medications and medical procedures being given an extension of their patents.

I know research and development costs a lot of money, but think of the high cost some patients have to pay for their brand name medications when there is no other alternative. When an extension is given, the patient could very likely not be able to afford it any longer.

The pharmaceutical companies make vast amounts of money in total, for all their products. I just don't think they should be allowed extensions.


@nathang - No, authors do not. Actually it depends on when the work was published. I don’t have the numbers in front of me, but there is a set number of years depending on when it was actually published.

It’s certainly more than 20 years. In some cases it’s the life of the author or seventy years or something like that. Afterwards it falls into the public domain.

If you’ve ever dreamed of publishing your own book, you could find a really old book that’s in the public domain, type it up, print it, and voila, you’ve just published your own book.

You can’t list yourself as the author of course; but you can put yourself as the editor after making a few tweaks.


I had no idea that patents, once they expired, could not be renewed. I guess it does make sense however. Otherwise no one could ever make a product like yours, forever, and you would enjoy a virtual, everlasting monopoly.

How does this situation compare with authors? Don’t authors have permanent copyrights to their work?


@SkyWhisperer - My understanding is that having patent pending is as good as having the patent, one on condition – the patent actually gets approved.

So if someone does steal your idea during the approval process, you can’t sue them unless you’ve actually been approved. If you’re rejected, you have no recourse.

However, patent pending is usually enough in and of itself to deter would be thieves. When you watch a TV infomercial and it displays “patent pending” in the fine print, that’s as good as law from what I understand.


So what happens to people who have “patent pending” and don’t have a patent yet?

What if someone creates a product that is identical to that of the inventor? Does the inventor have recourse?

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