How to buy a patent that has expired in the us
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How to Buy Expired Patents

Patents are a form of intellectual property that allows an inventor to exclusively use the item they’ve patented. Patents in the US are granted by the United States Patent and Trademark Office (USPTO) after submitting your completed patent application. Once the patent examiner reviews and approves your application, a patent is granted to you. That said, patents don’t last forever, so how do you purchase an expired patent? This article will detail the steps you need to take to buy an expired patent.

To keep a utility patent from expiring, an inventor must make maintenance payments on the patent, however sometimes inventors don’t make these mandatory payments, causing a patent to expire or lapse. If the patent lapses, this creates an opportunity for you to purchase the expired patent. So, how exactly do you go about purchasing an expired patent? We will cover this in more detail below.

When Can you Buy an Expired Patent?

If you’re looking to buy an expired patent, it’s important to know that utility patents typically expire at 4, 8, and 12 years after the USPTO issues them. To be exact, utility patents expire 3.5, 7.5, and 11.5 years into the patents life, but the USPTO offers a six month grace period, allowing the patent owner a grace period to pay the required maintenance fees.

If the patent owner chooses to renew their patent by making the maintenance fees within the 6 month period, the patent is renewed and will not lapse (expire).

How to Buy an Expired Patent?

You can buy an expired patent by performing a patent search through the USPTO website (more on this later) and checking to see if the patent has expired. Once you find a patent that has expired and you want to buy, you can go ahead and contact the patent owner to negotiate purchasing the patent.

Utility patents typically last for 20 year and often times patent holders don’t want to pay the periodic maintenance fees that are required to keep their patent live, as a result, many may list their patent for sale.

This is an opportunity for you to contact them and negotiate with them to purchase their patent. If you’re successful and the patent holder agrees to sell you their patent, you can reinstate the patent by paying the past due maintenance fees and paying a surcharge.

For the USPTO to revive a patent that has lapsed, an individual will have to pay $850 to $1,700. If you are considered to be a small entity, you will only have to pay $850. Individual inventors and small businesses that have under 500 employees are considered as small entities, and will only have to pay $850 to reinstate a lapsed patent.

In addition to this charge, you will have to pay past-due maintenance fees to revive a lapsed patent. Here are the maintenance fees you may have to pay if you’re individual inventor or you’re a business with no more than 500 employees:

  • 3.5 Years: $800

  • 7.5 Years: $1,800

  • 11.5 Years: $3,700

Can you Refile an Expired Patent?

If a patent has expired after reaching the 20 year mark, you can still contact the patent owner and negotiate a sale. You may be able to buy the invention and all right associated with the patent, however you will not be able to refile or renew the patent. This is so because patents are only good for 20 years and cannot be renewed past that date.

After a utility patent has been in place for 20 years or a design patent for 15 years, the invention becomes part of the public domain, meaning that the patent holder can no longer exclude others from using, making, and selling the invention. Said differently, you can use, make, sell, and import the invention because it no longer enjoys protection.

Summary For How to Find and Buy Expired Patents

Here is a quick summary of the steps you can follow to find and purchase an expired patent. If you want a more detailed step-by-step list on how to find and buy expired patents, see the section below.

  • Search the USPTO Patent Database for Patents
  • See instructions below how to search list of patents
  • Select the date range of the patents you’re interested in
  • Copy the patent number
  • Retrieve patent information from Public Patent Information System
  • Contact the patent owner if you’re interested in the patent they hold

How to Find Expired Patents?

Here is one way to find and purchase expired patents:

1) USPTO Patent Database

Head over to the USPTO Advanced Patent Search here

2) Input Title

Input the title of the patent you’re searching for. For example, if you are searching for patents relating to “bottles”, you would use the following text:


Once you hit the search button, you will see the following results related to bottles:

3) Date Range

Set a date range for the issue date of the patent to narrow down your search. If you want to search for patents relating to bottle that are issued within a certain time-frame, you would use the following search query:

ttl/(bottles) and

To set your own date range, replace the dates in the search query above. For example if you want to search for patents relating to bottles, issued between March 1, 2000 to April 5, 2018, you would use the following search query:

ttl/(bottles) and

4) Copy the Patent Number

5) Public Patent Application Information

Head over here to access the Public Patent Application Retrieval system.

Once you have accessed the system, click on the option to search by patent number and enter the patent number you retrieved from the previous step.

6) Check to See if Patent Expired

If you find that the status of the patent has expired, you will be able to contact the buyer to see whether they’re willing to sell it. Here are two examples, one where the patent has expired and one where the patent is still in effect.

Expired Patent

Here is an example of a patent that has not expired…

Patent Not Expired

How to Buy an Expired Patent?

Once you’ve located a patent that has expired, you can use the methods we’ve detailed above to contact and negotiate the sale of the patent with the patent holder. Like we mentioned previously, if the patent has lapsed for non-payment of maintenance fees, you will have to pay those fees, as well as an additional charge of $850 to reinstate the patent.

Remember that utility patents last for 20 years from the filing date of the patent and design patents last for 15 years from the date the patent is granted. Although you may be able to reinstate the patent, buying it will not extend the term of the patent.

That said, some patents expire because the patent term has ended. For those of you who are new to patents, patent term refers to the 20 year validity date of patents. After 20 years of filing a patent, patents expire and once they expire they become part of the public domain. When they become part of the public domain, you can use, manufacture, sell, and import the invention that was once protected without having to contact the patent holder (basically, they are free to use without anyone’s permission).

So, if you wanted to copy the expired patent that we referenced above, you could probably do so without even contacting or taking permission from the patent owner. That said, it’s always a good idea to consult with your attorney before copying someone else’s expired or abandoned patent because there is a chance that the inventor may have filed other patents that are related to the one you’re looking, so keep an eye out for such circumstances.

Benefits of Purchasing Expired Patents

  • Buying an expired patent provides you with the rights of the original patent holder provided that you pay the overdue maintenance fees and reinstatement fees.

  • When a patent expires, the buyer will be able to reinstate the patent by paying the outstanding maintenance fee and paying a reinstatement fee.

  • Buying an expired patent save you the hassle of having to invent and patent the invention yourself. You only have to purchase the patent, pay outstanding fees, and the patent is yours. You can spend your time improving and marketing the invention you just purchased.

  • If you happen to purchase a design patent or plant patent, you’ll be happy to know that you won’t need to pay any maintenance fees. Also, design patents last for 15 years from the day they’re granted, while plant patents last for 20 years from the patent application’s filing date.

Cons of Purchasing Expired Patents

  • The maintenance and reinstatement fees associated with patents can be huge if they have not paid for a long period of time. You have to determine whether it makes sense for you to purchase an expired patent by paying the outstanding maintenance fees and reinstatement fees.

  • Expired patents are sometimes involved in legal battles and lawsuits.

  • Please note that as patents move through 3.5, 7.5, and 11.5 years, the outstanding maintenance fees will continue to pile up, often presenting thousands of dollars of fees.

  • Patent trolls will often purchase expired patents by purchasing old patents and using them to sue other patent holders for patent infringement.

Frequently Asked Questions: How to Buy Expired Patents?

1) When Do Patents Expire?

To determine when a patent expires, you have to determine what type of patent you’re dealing with. Utility patents expire 20 years from the patent application filing date. Design patents expire 15 years from the patent grant date. Plant patents expire 20 years from the patent application filing date.

2) What are Maintenance Fees?

Maintenance fees are fees that are mandated by the USPTO. They are classified into three periods: E1, E2, and E3, they occur at 3.5, 7.5, and 11.5 years. If a patent holder does not pay these fees on time, they have a 6 month grace period to pay, if they do not pay, the patent expires for non-payment of maintenance fees.

3) How Much are the Maintenance Fees?

Maintenance fees increase as the patent ages. At 3.5 years, you will have to pay $800, at 7.5 years you will have to pay $1,800, and at 11.5 years you will have to pay $3,700. If the patent has expired, there are more fees to pay.

4) What happens when you pay the third maintenance fee?

Once you have paid the final maintenance fee at year 11.5, the patent will be valid for the full patent term of 20 years from the its filing date.

5) Do I Need a Lawyer When Purchasing an Expired Patent?

While you can talk to and negotiate the sale of a patent on your own, it’s recommended that you consult with an attorney in your jurisdiction because sometimes there are additional patents related to the one you’re trying to purchase and this could lead to trouble down the road. So, talking to an attorney is a good idea and may save you some money and trouble down the road.

How to Purchase an Expired Patent?

We have detailed the steps you will need to take to purchase an expired patent. We have also given the pros and cons of purchasing an expired patent. If you have any general questions or comments on how to buy an expired patent, please feel free to leave them in the comments section below.

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