Key Takeaways

  • Most U.S. utility patents last 20 years from the filing date, while design patents last 15 years from issuance, and plant patents last 20 years.
  • Patents filed before June 8, 1995, may have terms of 17 years from issuance rather than 20 years from filing.
  • Maintenance fees are required at 3.5, 7.5, and 11.5 years for utility patents; failure to pay can lead to early expiration.
  • Extensions and adjustments, such as Patent Term Adjustments (PTA) or Hatch-Waxman extensions for drugs, can extend patent life.
  • Once expired, the invention enters the public domain, meaning others can freely use, produce, and sell it.

Understanding patent time limits, including how long they remain valid and when you should file your application, can help protect your rights to your intellectual property, such as an invention or business method, from being exploited, used, or sold by someone other than you.

What is a Patent?

A patent is a government-issued license or exclusive rights to an invention that prevents other people from using, selling, and claiming it for their use without the permission of the patent owner while the patent is valid. Patents issued in the United States are only valid in the U.S. and its territories.

What Can I Patent?

There are almost no restrictions on what can be patented in the United States. If the invention or item solves a problem or produces an actual result and is man-made, it can be patented. Business methods and software are also some examples of the things that can be patented.

How Do I apply for a Patent?

Filing a patent in the United States requires that the person applying for the patent be the owner or inventor of the item, that the filing of the application is within the time limits specified and that certain conditions be met.

  • Ownership – United States Patent Law requires that the patent applicant be the registered owner or inventor of the item, the inventor's legal representative, or administrator of the inventor's estate. If more than one person is the inventor, then a joint application is to be filed. Employees of the United States Patent Office are prohibited from applying for patents.
  • Time Limits – Patents issued by the U.S. are guided by unique one-year statutory limitations and failure to comply with the following limitations can result in your application being denied:
    • the application must be filed within one year of the date the invention is offered for sale
    • the application must be filed within one year of the date of the invention being discussed or reported on in printed media
  • Conditions – In addition to the time limit, the inventor must also consider the following conditions which can factor into the approval of the patent application:
    • whether other individuals have filed or will file patents for the invention, which can delay approval or cause denial
    • when the other individuals will file — the inventor to file first has the greatest advantage.
    • the exact date the inventor publicly disclosed or discussed and offered for sale or sold the invention. The one-year statutory bar begins the moment the inventor discusses or sells the invention. Failure to keep note of the date can result in denial.

Types of Patents and Their Durations

The duration of a patent depends on its type:

  • Utility Patents – Cover new processes, machines, or compositions. They are valid for 20 years from the earliest non-provisional filing date. Maintenance fees must be paid to keep them active.
  • Design Patents – Protect ornamental designs for manufactured products. They last 15 years from the date of issuance, with no maintenance fees required.
  • Plant Patents – Apply to asexually reproduced plants and remain valid for 20 years from the filing date, also without maintenance fees.

Special rules apply for patents filed before June 8, 1995, which may follow the 17 years from issuance rule.

How Long Is a Patent Valid For?

Patents provide protection that lasts only as long as the patent remains valid. In the United States, most patents are valid for up to twenty years from the filing date. To keep the patent valid, owners are required to pay maintenance fees every three and a half years.

The exceptions to the twenty-year rule are those patents filed before June 8, 1995, with the patents remaining valid up to seventeen years from the date the patent was granted.

A simple way to determine the length of time your patent is valid, check the reference number. Patents with the date the permit was granted and the reference number “45” are valid up to seventeen years while patents with the date the patent was filed with the reference number “22”, are valid up to twenty years.

Patent Extensions and Adjustments

Patents sometimes last longer than their standard terms due to extensions or adjustments:

  • Patent Term Adjustment (PTA): Extends duration when the USPTO takes too long to process an application.
  • Patent Term Extension (PTE): Applies mainly to pharmaceuticals, biologics, and medical devices, compensating for time lost during regulatory approval under the Hatch-Waxman Act.
  • International Differences: Some countries allow additional extensions, but U.S. patents expire based on federal law and cannot be renewed indefinitely.

What Happens When My Patent Expires?

Patents expire when the time limit is up, or the patent has been abandoned due to non-payment of the maintenance fees. It is common for many patents to be abandoned before the time limit because of the increase in maintenance fees over the life of the patent.

Practical Impacts of Patent Expiration

When a patent ends, the invention enters the public domain, opening it up for anyone to use. Common impacts include:

  • Generic Competition: In pharmaceuticals, expiration typically allows generic manufacturers to enter the market, lowering prices and reducing exclusivity.
  • Innovation Opportunities: Competitors can build upon the original invention to create new products or improvements.
  • Business Strategy: Some companies build strong patent portfolios to stagger expiration dates and maintain long-term market protection.

Once the patent expires or is abandoned, the protection from exploitation wanes. You no longer own the exclusive rights to the invention, and the proprietary information about your invention becomes available to the public. This means other people can create, improve upon, sell, import, distribute, and claim your invention for themselves without your permission.

Frequently Asked Questions

  1. How long is a patent good for in the U.S.?
    Most utility and plant patents last 20 years from the filing date, while design patents last 15 years from issuance.
  2. Can a patent be renewed after it expires?
    No. Once a patent expires, it cannot be renewed. However, extensions like PTA or PTE may lengthen the term before expiration.
  3. What happens if I don’t pay maintenance fees?
    If maintenance fees for a utility patent are not paid at 3.5, 7.5, and 11.5 years, the patent may expire early.
  4. Do patents last the same worldwide?
    No. Patent laws vary by country. While many follow the 20-year rule for utility patents, details differ internationally.
  5. Why do drug patents sometimes last longer?
    Pharmaceutical patents may benefit from Hatch-Waxman extensions, granting up to 5 extra years to offset regulatory delays.

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