An accurate calculation of MOSFET capacitance-voltage (C-V) characteristics has to account for the bulk charge which is affected by nonuniform doping profiles and short-channel effects. In our approach based on the Unified Charge Control Model (UCCM), we relate the voltage dependencies of the bulk charge to the standard parameters of the body plots which are routinely measured during MOSFET characterization. The results of the C-V calculations based on this model are in good agreement with our experimental data and with the calculations based on the standard BSIM model. Compared to the BSIM simulations, our model more accurately describes capacitances related to the bulk charge and the device subthreshold behavior. The model is suitable for incorporation into circuit simulators.