N.Y. Comp. Codes R. & Regs. tit. 19, § 212.4 – Weight classes of contestants.

(a) The times and places of all weighing in ceremonies shall be as determined by the commission and all participants shall be weighed in on scales approved by the commission and in the presence of their opponent and representatives of the commission, unless otherwise directed or authorized by the commission. In the event of a postponement of a contest or exhibition for more than 24 hours for any reason, a second weigh-in and additional physical examination may be required by the commission on the day of or day prior to the date to which the contest or exhibition has been adjourned.

(b) Except as otherwise directed by the commission, the weight classes for contestants competing in professional mixed martial arts contest or exhibitions are as follows:

Weight class		Weight difference allowance
Strawweight	Up to and including 115 pounds	Not more than 3 pounds
Flyweight	Over 115 to 125 pounds	Not more than 4 pounds
Bantamweight	Over 125 to 135 pounds	Not more than 5 pounds
Featherweight	Over 135 to 145 pounds	Not more than 7 pounds
Lightweight	Over 145 to 155 pounds	Not more than 7 pounds
Welterweight	Over 155 to 170 pounds	Not more than 7 pounds
Middleweight	Over 170 to 185 pounds	Not more than 9 pounds
Light Heavyweight	Over 185 to 205 pounds	Not more than 12 pounds
Heavyweight	Over 205 to 265 pounds	Not more than 25 pounds
Super Heavyweight	Over 265 pounds	No limit

(c) In non-championship matches there shall be a one pound weight allowance from the specified contract weight. In championship matches the participants must weigh no more than the maximum weight allowed for the relevant weight class.
(d) The commission may, in its discretion, waive the maximum weight difference allowance as provided in subdivision (b) of this section, so long as the official weight of both competitors is within the same weight class and both competitors consent to the waiver in writing.