Among the renewable energy types, wind provides intermittent but environmentally friendly energy source that does not pollute atmosphere. Wind power calculations are initiated from the kinetic energy definition, and finally, the power is found as proportional to the half (1/2) of air density multiplied by the wind velocity cube. In this paper, wind power formulation is derived first by use of kinetic energy definition and then the basic physical definitions of power as the ratio of work per time, the work as the force multiplied by the distance and the force as the change of momentum. These considerations lead to wind power formulation with 1/3 factor instead of 1/2. Furthermore, formulation with factor of 1/3 gives results close to Betz limit within 10% difference at very high wind speeds (>12m/s), which remains within practically acceptable limits. Copyright (c) 2012 John Wiley & Sons, Ltd.