The device relates to a system for predicting the period for children to safely wear newly acquired footwear without the risk of damage to their growing feet, which is directly applicable in shoe shops (at their computer cash registers). The essence of the solution for a system for predicting the period for children to safely wear newly acquired footwear rests in the fact that it contains an input module measuring foot length and input of information about the age of the monitored child to which is linked a model for predicting the growth of the child's foot by applying the laws of growth, possibly also including genetic and local influences, connected to a comparative and inferential module establishing the predicted course of growth in foot length of the monitored child, to which is then linked an output module designating the nearest date for the necessary replacement of shoe size for the monitored child.
