The total population balance equation for granulation is examined when coalescence as well as crushing and layering are modes of growth. Previous solutions for the case of random coalescence are inadequate for describing a wide variety of granulating systems. A single parameter model is proposed to describe the reduced number density function of granules as a function of reduced granule size. Further, the relationship between model parameter and the empirical ballability index proposed in the literature is shown to be monotonic. The present model correlates very well the data on a wide variety of granulating systems besides providing a good approximate solution to the population balance equation. © 1982.