How Long Is a Patent Valid?

by Grygor Scott

    A patent is a governmental grant of a short-term monopoly to inventors. U.S. patent laws enable a patent holder to prevent others from making, using or selling the patented invention for a specific time period. How long a patent remains valid depends on the type of patent and other factors.

    Acquiring a Patent

    To receive a patent, an inventor must file a patent application with the U.S. Patent and Trademark Office. A patent examiner examines the application. If the application establishes that the invention satisfies the legal requirements for a patent, the examiner will approve the application. The Patent and Trademark Office then sends the inventor a patent certificate.

    Determining the Effective Date

    A patent’s term begins on the date that its application was filed with the Patent and Trademark Office. A patent’s effective date is the filing date rather than the approval date because extending an approved patent’s legal protections back to the filing date deters others from exploiting an invention while the inventor’s patent application is under review. In rare cases, a patent’s term starts after the filing date. The Patent and Trademark Office sometimes grants a patent holder a later effective date if there was an unusual delay in examining the patent application.

    Utility and Plant Patent Term

    U.S. law recognizes three different types of patents. Most patents protect new, useful machines, manufactured items, and processes. This type of patent is known as a utility patent. New, distinct varieties of plant life may also be patented. All utility and plant patents filed after June 8, 1995, have a term of 20 years. Patents filed before that date have a term of either 17 years from the date the patent was issued or 20 years from its earliest filing date, whichever results in the longer term.

    Design Patent Term

    The third type of patent is a design patent. It protects the distinct ornamental features of a manufactured item. These features may be a distinctive shape or a novel exterior design. Design patents have a term of 14 years.

    Patent Expiration

    A patent expires when its term ends. A patent may become invalid before its term ends if the patent owner fails to pay required maintenance fees to the Patent and Trademark Office. Maintenance fees are due in years three, seven and 11 of a patent’s term. The Patent and Trademark Office gives patent holders a six-month grace period to pay maintenance fees. A patent may also be invalidated when a court trying a patent infringement lawsuit rules that the patent fails to meet the legal requirements for patent approval.

    About the Author

    Grygor Scott has written professionally since 1991, with a focus on law, government, food and travel. His work has appeared in "New York Resident" and on several websites. The author of more than 20 nonfiction books, Scott graduated with honors from the University of North Carolina School of Law.