The accuracy of standard RedOx potential calculation in water solution by semi- empirical approximations (AM1, PM7 and RM1) with various continual solvation models (COSMO, PCM, SM5.2 and SM5C) was considered. On a wide set of electroactive compounds (121 pcs.) we showed that errors of E-RedOx(0) calculation decrease among PM7 > AM1 > RM1 and COSMO > PCM > SM5.2 > SM5C. However parameterization is more important than solvation model, thus PCM/RM1 is more accurate than SM5C/AM1. The accuracy of RedOx potential calculation depends on the electroactive functional group. PCM/RM1 demonstrates the best accuracy on anilines, approaching to ab initio methods SM5.42R/BPW91/DZVP// BPW91/cc- pVDZ (MADPCM/RM1(anilines) = 0.09 vs MAD(SM5.42R/BPW91/DZVP//BPW91/cc- pVDZ) (anilines) = 0.09). For O-containing molecules accuracy of E(RedOx c)(0)alculation was worse, MAD(PCM/RM1()phenols) = 0.92 and MAD(PCM/RM1)(diphenols) = 0.68. Calculated values can be correlated by the equation E-RedOx(0) (calc) = 0.2671* E-RedOx(0)(PCM/RM1) + 0.2430. MO energies provided by PCM/RM1 can be used for E-RedOx approximation. The routine equation E-Red (Ox) = -0,1494* EHOMO (X) -0,1416 * ELUMO (X) E-MO2 - 0,5602 (R = 0,7420) has good correlation and is more practical, than the best equation E-Red/Ox = -0,1752 * E-HOMO (X+*) -0,1653* E-LUMO (X) E-MO2 -1,0146 (R = 0,7762), because only one calculation of electroactive compound X is needed. (c) 2018 Elsevier Ltd. All rights reserved.