An engineering correlation is presented for the density of multicomponent aqueous electrolytes. The correlation provides insight into the terms that contribute to the density of aqueous electrolytes and demonstrates how they can be estimated from readily available information. In its simplest form, the model has only pure ion parameters and provides moderate accuracy; the average errors are similar to1% while maximum errors can be slightly greater than 5%. When anion-cation binary interaction parameters are included in the correlation, the errors for the density of single aqueous electrolytes become very small, with maximum errors rarely exceeding 1%. No further parameters are necessary for multicomponent electrolytes, but like-ion binary parameters are sometimes preferred to attain a highly accurate correlation.