The disclosure presents a process for calibrating a diversion model for a treatment stage of a hydraulic fracturing well site. The process can pump a portion of the proppant into the wellbore, flush the wellbore with clean HF fluid, and then perform a diagnostic test to determine a near-wellbore (NWB) flow resistance parameter. Next, diverter material can be distributed into the wellbore and the amount of diverter material delivered to each active perforation cluster can be estimated. A second diagnostic test can be performed followed by computing diversion model parameters such as a near-wellbore zone length parameter for perforation clusters capable of receiving HF fluid. In another aspect, a system is disclosed that can direct operations of a well site pump and collect data from surface and downhole diagnostic sensors, and then use the collected data for the diversion model calibration process.