  We perform coagulation & fragmentation simulations to understand grain growth
in T Tauri & brown dwarf discs. We present a physically-motivated approach
using a probability distribution function for the collision velocities and
separating the deterministic & stochastic velocities. We find growth to larger
sizes compared to other models. Furthermore, if brown dwarf discs are
scaled-down versions of T Tauri discs (in terms of stellar & disc mass, and
disc radius), growth at the same location with respect to the outer edge occurs
to similar sizes in both discs.
