An airfoil for a rotor blade including an uncoated profile substantially in accordance with Cartesian coordinate values of X, Y and Z to facilitate balancing performance and durability of the rotor blade and to facilitate improving an operating efficiency of a high-pressure turbine is provided. The profile is carried only to four decimal places, wherein Y represents a distance from a platform on which the airfoil is mounted, and X and Z are coordinates defining the profile at each distance Y from the platform.