Duration of a Utility Patent
The most critical element determining how long a utility patent lasts is the payment of maintenance fees. Maintenance fees must first be paid 3.5 years after the patent was issued, and then must be paid again at the 7.5- and 11.5-year marks. The fees themselves are steep: $400, $900, and $1,850 respectively for a micro entity. Some utility patents issued to larger companies require a much larger investment, totaling over $12,000. It should also be noted that the fees may be changed. While the maximum duration of a utility patent is 20 years, a patent can expire much sooner if the maintenance fees have not been paid.
Certain circumstances can also affect the duration of a patent. The most important of these is a terminal disclaimer, which applies when you file a second patent that is very similar to another patent you've already filed. Because some part of the invention is already obvious (well-known and understood) because of the prior patent, the second patent may have some limitations. The USPTO may require you to file a terminal disclaimer, which is an agreement that places limits on the second patent. If a terminal disclaimer is filed, the patent will expire when the original patent does. In addition, after a terminal disclaimer has been filed, a patent can also receive a duration adjustment if the original patent referenced by the disclaimer has already received a duration adjustment.
Finally, patents can sometimes be extended under provision 35 U.S.C. 156, which may come into play if you were prevented from commercially marketing your patent because of a pending approval from a regulatory agency. Generally this only applies if you have a patent for human or animal drugs, food or color additives, medical devices, or other products that are regulated by the FDA or another government agency.
This article contains general legal information and does not contain legal advice. Rocket Lawyer is not a law firm or a substitute for an attorney or law firm. The law is complex and changes often. For legal advice, please ask a lawyer.