Microstructural evolution during sintering can be simulated using the Potts kinetic Monte Carlo model. This model simulates detailed evolution of the powder particles, pore shapes, neck growth, and other microstructural features with sufficient resolution over a sufficiently large compact so that interfacial energies and curvatures of a statistically representative sample of surfaces in a complex compact can be obtained from the simulations. In this work, we present a technique based on measuring curvature of surfaces to obtain sintering stress of sintering powder compacts with arbitrarily complex geometries of powder size and powder shape distributions. The method is applied to three distinct powder compacts with very different sintering behavior to obtain sintering stress for each of these cases. The sintering stress for the three simulated cases were distinct and dependent on the geometric microstructural details of the powder compacts.