Its easy to calculate the approximate capacitance by calculating the capacitance/um2 for the gate of a MOS and then multiplying by area, but you can probably get a good approximation by biasing the gate with a current source and then using: i=C.dV/dt to calculate the capacitance
I want to model gate drivers in an interconnect configuration and set an analytic expression for Delay. That i need to model an Invertor as driver with internal resistor and in/out parasitic capacitors. Then there is no other way to evaluate the invertor parameters.
Im not sure about this, but you can possibly switch the inverter, then measure the average current at the output and use this with i=C.dV/dt to compute the capacitance