This paper presents a new method to calculate solid-state effects on NMR chemical shifts. Using full crystal potentials, this new method (CPPCh) eliminates the need to arbitrarily select the point charges that are included in the calculations of the NMR chemical shieldings to take into account intermolecular effects. By eliminating the arbitrary selection of the point charges, the method provides a mechanism to systematically improve the simulation of intermolecular effects on chemical shielding calculations. This new method has been applied to the calculation of the 31P NMR chemical shifts tensors in P4S3. The shielding calculations were done using the DFT approach with the BLYP gradient corrected exchange correlation functional. This method was selected to calculate the 31P chemical shifts because it includes electron correlation effects at a reasonable cost.