N.Y. Comp. Codes R. & Regs. tit. 6, § 195.3 – Classification and size limitations of authorized signs.

(a) Standard small: a sign one foot high by three feet wide.
(b) Small: a sign not exceeding three square feet in area.
(c) Standard medium: a sign 2 ½ feet high by four feet wide.
(d) Medium: a sign not exceeding 10 square feet in area.
Note:
Authorized signs may be lettered on both sides.

Authorized signs shall be classified and limited in size according to the outside height and width or the total area of one side thereof, exclusive of the necessary supporting structure, as follows: