(PDC) Potential Derived Charges is a package to describe macromolecules as a limited set of optimized, discrete effective charges immersed in a uniform dielectric.These effective charges are fitted to best reproduce the molecular electrostatic potential calculated from the numerical solution of the Poisson-Boltzmann equation. By using effective charges one can greatly reduce the computational cost of evaluating the electrostatic forces and energies in molecular simulations, especially for the systems that are too large to be studied on the atomic level. Effective charges can be also employed in various coarse-grained approaches.