A model of cotton (Góssypium sp) lint yield that equated yield to the volume of a parallelepiped with three dimensions was developed by Kerr. The model is extended to basic units by dividing the axes of the parallelepiped and the seed is recognized as the basic unit of yield. Yield per seed, per boll, and per unit area of land can be stated in equation form by using the divisions of the axes. The relative contributions of the primary lint yield components decrease as the complexity of the model increases from yield/seed to yield/unit area of land. The summation of each model has an upper R3 limit of 1.0. Therefore by the inclusion of additional components, the relative contribution of yield components from the previous models must decrease. Data are presented that illustrate a use of the model to define the component of yield more susceptible to alteration to increase yield.