How long is a patent valid? How long does a patent last?

Utility and plant patents are exercisable for up to 20 years from the date the first non-provisional application for patent was filed.

A design patent is exercisable for a term of 15 years from the date of grant.

Maintenance fees are required to be paid in intervals after the utility patent is issued in order to keep it in force.

Provisional patent applications stay “alive” for a year, but will go abandoned if a non-provisional application is not filed within 12 months of the filing date of the provisional application and claiming priority to the provisional application.