New Jersey Statutes Title 46. Property 46 § 10B-3

A mortgagor shall have the right, during any 6 month period beginning with the date of the mortgage loan, to pay, without charge or penalty, an additional sum of $50.00, or multiples thereof, on account of the principal amount owing on a mortgage loan, provided that the additional sums so paid and the principal payments required to be made by the terms of such mortgage loan during such 6 month period do not together exceed in any such 6 month period 33 1/3 % of the face amount of such mortgage loan. The right to make additional payments as provided by this section shall not be cumulative, and to the extent that it is not exercised during any 6 month period, shall lapse.