This paper presents a correlation to predict the speed of sound of n-alkanes with a carbon number greater than or equal to five and their mixtures. The correlation for the speed of sound follows the form of the Tait equation with variables: temperature, pressure and equivalent carbon number of the mixture. Part of this equation is a correlation for the atmospheric pressure sound speed of n-alkanes. The average absolute percentage deviation of the atmospheric equation from the literature experimental speed of sound values is 0.1%. The Tait equation uses 3000 experimental points at high pressures and has an average absolute percentage deviation of 0.17% from experimental measurements. (c) 2012 Elsevier B.V. All rights reserved.