A flow rate of blood through an implantable blood pump is determined based on a parameter related to the flow, such as a parameter related to thrust on the rotor of the pump. An amount of current supplied to the pump is used to determine each of a first flow rate value and second flow rate values. Each of the first and second flow rate values, in combination with the parameter related to thrust on the rotor of the pump, are used to calculate a flow rate of blood through the pump.