A simple method for calibrating high-performance SEC/GPC systems is presented. This technique sequentially finds the correct slope, D-2, by tracking the calculated polydisperity, P, using arbitrary calibration slopes from which the intercept, D-1, is ultimately back-calculated. The ease of application and relative efficiency of this search technique are highlighted and discussed. Theoretical justification of the simple form of the convergence equation is presented using two distribution models-the Gaussian (pseudo-Flory) and the sine (cosine) exponential models.