Depletion of high grade lump ore and increased blast furnace productivity with the use of prepared burden has resulted in increased use of iron ore sinter and pellets. There is considerable interest in including fine iron ore concentrate and micropellets into sinter mixes. These materials need to be accommodated in the sinter mix without adversely affecting the permeability of the sinter bed. Addition of fine concentrate and micropellets to a sinter mix will significantly affect the particle size distribution of the granules in the sinter feed. This paper describes the prediction of granule size distribution using the model developed by Litster. The effect of concentrate and micropellet addition on the model accuracy was evaluated by comparing the experimental and predicted Sauter mean diameters of the granules and evaluating the mean absolute percentage error (MAPE). It was confirmed that Litster's model can be applied to the tested sinter mixtures to predict the mean granule size, with a MAPE of less than 10%. The results of the model also provide a scope for comparing mean granule sizes, particle growth and the ratio of finer to nuclei particles as the amounts of concentrate and micropellets increase. The granule size decreased with addition of concentrate while the particle growth and ratio of finer to nuclei particles increased. For sinter mixtures that contain micropellets, the granule size, particle growth and ratio of finer to nuclei particles decreased with an increase in the mass fraction of micropellets. (C) 2016 Elsevier B.V. All rights reserved.