Utility patents and design patents each have different lifespans. Design patents filed prior to May 13, 2015, have a term of 14 years from issuance. Design patents filed on or after May 13, 2015, have a term of 15 years from issuance. Determining the life of a utility patent is a little more complicated.
As a general rule, utility patents filed after June 8, 1995, have a life of 20 years from the date of filing of the earliest non-provisional application to which it claims priority. It is important to note that the term of a utility patent is tied to the earliest filing date of a non-provisional patent application to which it claims priority. The consequence is that by filing a provisional patent application as the priority application, then filing the non-provisional patent application one year later, you are able to file a patent application whose lifespan will be 21 years from the earliest filing date.
In addition, delays in the grant of the patent caused by the patent office’s examination process can results in patent term extensions. As a result, some patents will have lives that extend past 20 years from the earliest non-provisional filing date.
Further complicating the lifespan of utility patents, they can be subject to terminal disclaimers. A terminal disclaimer is required by the patent office when the claims in two patents overlap such that they could be said to cover the same invention. The terminal disclaimer ties the lifespan of two (or more) patents together so that they each expire at the same time.
A last consideration is whether the utility patent has been appropriately maintained. Once a utility patent issues, maintenance fees are required to keep the patent in force. A first maintenance fee is due approximately 4 years after the patent issues, the second maintenance fee is due approximately 8 years after the patent issues and the third and final maintenance fee is due approximately 12 years from the issue date. Non-payment of any maintenance fee when it is due results in abandonment of the patent.