Abstract: A ladle preheating system and method in which heat input rate to the ladle is calculated and monitored throughout the preheating period, calculating the moving average slope representing change over time of the rate of change of heat input, correcting the moving average slope for unavoidable variations in the measurements of the heat input rate, calculating the change of the moving average slope over time (the approximate second derivative), and signaling to an operator the readiness of the ladle based upon this second derivative's falling below a preset criteria indicating a fully preheated ladle.