In this paper we provide an analytical expression of the capacity outage probability for Coordinated Multiple Point (CoMP) downlink transmission in Rayleigh fading. The theoretical derivation and simulation results match perfectly. Used in dense urban interference limited networks, CoMP is expected to improve cell-edge users' throughput and allow a better coverage and fairness. We demonstrate that our closed-form derivation can be helpful to maximise the capacity with outage and the goodput, by tuning appropriately the transmission data-rate and selecting optimal set of cooperating stations.