A method, system, and medium are provided for estimating user throughput as a function of network load. The function that governs a relationship between user throughput and network load is derived after simulating network traffic during busy hours on a wireless network. The simulated traffic is shaped to be similar to packet traffic received on the network. In turn, the simulated traffic is assigned to one or more carriers that are configured to resemble the network carriers. Upon processing the simulated traffic, user throughput is calculated and a function is derived from the network load during the busy hour and the calculated user throughput. The derived function is employed to predict the load at which user throughput falls below acceptable levels.