We have developed software to simulate the development of non-equilibrium latex particle morphologies produced by seeded emulsion polymerization. The diffusion of second stage polymer radicals within seed particles controls the development of morphology in a large number of systems. Knowledge of the conditions present within the latex particles during the reaction is required in order to model this diffusion process, and this makes it necessary to first simulate the kinetics of the polymerization. The program considers both the water phase and particle phase reactions, and can simulate polymerizations carried out under either batch or semi-batch conditions. The model predictions agree well with experimental results both in terms of the polymerization kinetics and the development of particle morphology.