A packet-based communications network is dimensioned based on a maximum number of users able to receive a predetermined target throughput of data over a predetermined number of channels. For each of an incremental number of users, at least one blocking probability is calculated, based on a traffic distribution model, and a service delay is calculated, based on the blocking probability. An iterative throughput, corresponding to each of the incremental number of users, is determined based on the corresponding blocking probability and service delay. Each iterative throughput is compared to the target throughput. The maximum number of users is identified as the number of users having a corresponding iterative throughput that is the largest iterative throughput less than target throughput.