Marginal utility is the "change in total utility obtained by consuming one more unit of a good".
Marginal utility evaluates the additional satisfaction a customer earns from consuming extra units of products or services. The idea of marginal utility is utilized by economists to decide the amount of a thing buyers are happy to buy. Positive peripheral utility happens when the utilization of an extra thing builds the total utility, while negative marginal utility occurs when the utilization of an extra thing diminishes the total utility.