The finite field method was used to calculate the static first and second hyperpolarizabilities (beta and gamma) for organic molecules. The dependence of beta and gamma on the applied electric field strength was investigated and used to determine the optimal field strength for each individual molecule. For gamma, we designed a protocol that uses the maximum atomic distance within the molecule along the direction of the applied field to estimate optimal field strengths. However, beta is nearly independent of the descriptors we considered, and largely depends on the composition (e.g., the presence of certain functional groups) of the molecule. (C) 2017 Elsevier B.V. All rights reserved.