Ionic conductivity is a foremost transport property that is extensively used to characterize and screen electrolyte systems. Although bulk measurements are done on the macroscopic scale, electrolytic conductivity has its foundation on molecular-scale interactions between solvent and ionic species. Correct interpretations of these molecular interactions and related quantities enable a balanced, comprehensive understanding of conductivity behavior with respect to system conditions (solvent composition, salt concentration and temperature). This work introduces a new methodology that achieves accurate predictions of electrolyte conductivity for a wide range of conditions, based on molecular, physical, and chemical terms. The formalism is universal, making it valid for aqueous and nonaqueous systems alike. The immediate application of the resultant model is candidate electrolytes for lithium-ion and sodium-ion batteries, although many other applications abound for systems that utilize liquid electrolytes. Conductivity predictions are compared to experimental data for a number of electrolytes over a wide range of conditions, demonstrating that exceptional accuracy is attained because the robust model captures multiple salient contributions to conductivity behavior. Model accuracy is well maintained over multi-solvent systems and for extended salt concentrations. (C) 2016 Elsevier Ltd. All rights reserved.