Definition[edit | edit source]
U.S. patent law[edit | edit source]
Maintenance fees are fees paid at three intervals during the life of a patent that must be paid to keep the patent in force for its entire 20-year term. The fee is now payable at 3 1/2, 7 1/2, and 11 1/2 years from the date of issuance. A late fee is permitted, but a surcharge is imposed.