In this paper, the Heidaryan and Jarrahian equation of state (Heidaryan and Jarrahian, 2013) has been adapted as a first worldwide cubic EOS to calculate the density of dry natural gases, wet natural gases, and single-phase gas condensates "sweet and sour mixtures" (up to 73.85, 97.63 and 38.37 mol percent of H2S, CO2, and N-2 respectively) even when the gas composition is unknown, through new gas specific gravity correlation equations. Correction terms of water content as high as 10 mol percent of H2O and hythane (natural gas + hydrogen) as high as 74.9 mol percent of H-2 were obtained. The equation of state was validated with 8985 experimental compressibility factor data points from 308 different mixtures in a range of atmospheric pressures up to 1570 bar and temperatures from -94 to 210 degrees C. (C) 2014 Elsevier Ltd. All rights reserved.