An attempt has been made to propose accurate equations for correlating the surface tension of binary liquid mixtures. The method is applicable to the systems comprising of components with widely different molecular sizes. Two adjustable parameters, delta(p) and delta(m) obtained from the least squares analyses of the surface tension-composition data are reported for a number of systems. Temperature dependence of delta(p) and delta(m) is demonstrated for a few systems. The framework of operational equations has later been applied to cover multi-component systems comprising of fused salts with a single liquid component in full mole fraction range. Excellent fits of the surface tension for binary, ternary and multi-component ionic systems in aqueous or non-aqueous media have been obtained from the proposed method. The surface tension-composition data of 59 different types of systems with about 400 data points can be correlated by the equation with an average percent deviation of about 0.61. In contrast to previous equations from literature to calculate surface tension data, the proposed correlation is noted to be more accurate in different situations.