The terms of patent protection vary from country to country and with the type of patent. In the United States, a utility patent generally is valid for 20 years as measured from the date of the filing of the application - not from the date the patent was granted. (U.S. patents on applications filed before June 8, 1995 previously had provided 17 years of patent protection). Utility patents may expire early if required maintenance fees are not paid.
A U.S. design patent has a term of 14 years from the date of the grant for applications filed before May 13, 2015, and 15 years from the date of the grant for applications filed on or after May 13, 2015. Maintenance fees are not required for design patents.