The induction times at supersaturations of 1.15-1.24 and the metastable zone widths (MSZWs) with cooling rates of 6.0-30.0 K/h have been determined in the system of dicyandiamide and water. A model based on the accumulation of nucleation potential, derived from the classical nucleation theory, has been applied to estimate the critical nucleation potential and preexponential factor. The estimated values based on the experimental induction times or based on the experimental MSZWs were fairly consistent with each other. The pre-exponential factor was assumed to be constant in the model, while the modifications of the preexponential factor, dependent on the supersaturation, have been introduced to the model for more consistent between the estimations based on the induction time and the MSZW.