Key Takeaways

  • Patents enter the public domain once their protection period ends, usually 20 years from the filing date for utility patents and 15 years from issuance for design patents.
  • Patents can also fall into the public domain early if the owner fails to pay maintenance fees, abandons the patent, or if the patent is declared invalid.
  • Once a patent is in the public domain, anyone may use, make, or sell the invention without needing permission or paying royalties.
  • Public domain patents promote innovation, research, and industry growth by allowing free use of previously protected technologies.
  • Tools like the USPTO database, Michigan Tech’s search system, and NASA’s database make it easier to identify expired or abandoned patents.

What Are Public Domain Patents?

Public domain patents are created when a patent is now publicly usable. The patent may be in the public domain because it hasn't been properly maintained, or because its term has expired. The patent system was created with the founding of the United States. Written into the United States Constitution, it has given inventors a period of time whereby their use of an invention is protected.

Eventually, all patents enter the public domain where anyone can use and build on them. Even if a patent is properly maintained, they expire after several years. Many patents enter the public domain far earlier however than their expiration date. This happens when the patent or trademark is either abandoned or not maintained properly, such as through the maintenance fee schedule required.

Many more patents than you might expect to enter the public domain before their expiration date. In fact, roughly 50 percent of patents do.

It used to be difficult to determine what patents had entered the public domain, as there were few public monitoring tools to continually track it. Each patent would have to be monitored through the USPTO's database. However recent databases have been created to monitor patents that fall into the public domain, such as Michigan Tech's public search system.

It is also possible to modify the search terms on the USPTO website to find patents that have expired by setting a minimum 20-year time since granting.

Here are some statistics on the percentage of patents abandoned per year due to lack of fee payment:

  • 2015: 21.79%
  • 2014: 20.52%
  • 2009: 17.52%
  • 2005: 15.38%

Patent policy remains controversial. Due to the roughly two decades most patents receive, many others aren't able to utilize the technology as rapidly. Particularly in fields that are developing extremely rapidly, such as software and Internet services, this can be a problem.

While patents were created with the intent to release the patent's technical details to the public with the application, nowadays inventions are becoming so complex that many of the applications do not sufficiently describe the invention enough for the public to utilize effectively.

Copyrights operate under a different set of rules. Copyrights may last a lot longer, such as 70 years. When looking at copyrights it is essential to carefully examine when it is going to expire and if it has been renewed.

When Does a Patent Enter the Public Domain?

Patents typically enter the public domain once their statutory protection period has ended. For utility patents, this is generally 20 years from the earliest filing date, while design patents last 15 years from issuance. However, many patents never reach full term. If an inventor does not pay the required maintenance fees at 3.5, 7.5, and 11.5 years, the patent lapses and immediately becomes part of the public domain. Similarly, if a patent holder abandons the invention or if a court declares the patent invalid, the technology may enter the public domain before the end of its maximum term.

This means that patents can enter the public domain at different times depending on their type and whether they were actively maintained. Understanding these rules is crucial for anyone asking “when does a patent enter the public domain?”, as it varies by circumstances rather than a single uniform timeline.

NASA's Searchable Database of Public Domain Patents

NASA has long been at the forefront of technological development in multiple sectors, due to the complexity of aeronautics.

NASA has not only been involved in propulsion technologies but everything ranging from chemicals to nutrition, from protective materials to engines, due to the various demands of space travel on the vehicles and occupants.

As NASA continues to develop, it remains a source for many emerging and essential technologies that continue to push entire industries forward.

Many NASA technologies remain of great public interest and NASA does release certain patents to the public.

For example, in May 2016 they released over 56 patents into the public domain. Furthermore, they also opened an internet database that allowed the public to study their expired patents.

The release wasn't as beneficial to the industry as it may initially seem. The patents were specifically chosen as ones that were not likely to be too useful for businesses, as the patents were either in fields with weak markets or were not sufficiently developed.

Nonetheless, the released patents are useful for public interest and study and also may have unexpected contributions to technological and commercial research and development.

Even though many NASA technologies may seem only related to spaceflight, in fact, many different industries may find some uses for these NASA patents in unexpected ways. For example, propulsion technologies could find uses in strengthening truck engines, while NASA's medical research could benefit entire biological and chemical sectors.

NASA released these technologies with the intent to bolster overall societal technological development. Even though the patents released were identified as not extremely novel, nonetheless creative inventors, researchers, and companies likely will make some good use out of them.

What Happens Once a Patent Is in the Public Domain?

When a patent enters the public domain, exclusive rights are lost, and the invention becomes freely available for public use. Competitors, researchers, and entrepreneurs may manufacture, sell, or improve upon the technology without needing authorization from the original patent holder. This transition benefits industries by reducing costs and fostering innovation, since the barriers of licensing fees or litigation threats are removed.

However, while the invention itself becomes public property, the original patent documentation remains valuable as a technical resource. Many businesses rely on these documents to better understand past innovations and to inspire new improvements. In this way, expired patents continue to contribute to scientific and commercial progress even after their legal protection ends.

Why Public Domain Patents Matter

Public domain patents play a critical role in balancing private rights and public benefit. By granting inventors a limited period of exclusivity, patent law encourages investment in innovation. But by eventually releasing those inventions to the public, the system ensures that society can benefit from knowledge-sharing and competition.

Key benefits of public domain patents include:

  • Encouraging new businesses by lowering entry barriers.
  • Reducing costs of using established technologies.
  • Advancing research and education, as universities and startups can access proven ideas.
  • Stimulating innovation, since inventors can build upon existing designs.

This dual structure ensures patents fulfill their constitutional purpose: promoting progress while eventually becoming part of the collective technological base.

Frequently Asked Questions

1. When does a patent enter the public domain?

A patent usually enters the public domain after 20 years for utility patents or 15 years for design patents, unless it lapses earlier due to nonpayment of maintenance fees or abandonment.

2. Can a patent enter the public domain before it expires?

Yes. If the patent holder fails to pay maintenance fees, abandons the patent, or if the patent is declared invalid in court, it may enter the public domain before the maximum term ends.

3. What happens once a patent is in the public domain?

Anyone may use, sell, or build upon the invention without the need for licensing or paying royalties, fostering innovation and competition.

4. How can I check if a patent is in the public domain?

You can use the USPTO database, Michigan Tech’s search tool, or specialized databases like NASA’s to identify expired or abandoned patents.

5. Why are public domain patents important?

They provide societal benefits by allowing free use of technologies, lowering costs, advancing research, and encouraging new product development.

If you need help with public domain patents, you can post your legal need on UpCounsel’s marketplace. UpCounsel accepts only the top 5 percent of lawyers to its site. Lawyers on UpCounsel come from law schools such as Harvard Law and Yale Law and average 14 years of legal experience, including work with or on behalf of companies like Google, Menlo Ventures, and Airbnb.