Modeling the spark plasma sintering of ceramics can be a very time-consuming task requiring high temperature sintering tests with fully dense/porous specimens in different configurations. Final stage sintering requires a particular attention as the densification kinetic is closely related to the grain growth phenomenon. In this work, we describe a combined master sintering curve and regression method which is able to determine all sintering model parameters. The original approach of this study lies in the possibility to estimate the grain size curve with the grain growth disturbance on the densification kinetics at the final stage. The model and grain size curve estimation reproduce well the experimental data points.