us postal service cost per pound refers to the price that USPS charges for shipping a package based on its weight. USPS uses a weight-based pricing structure for most of its services, including Priority Mail and First-Class Mail. The cost per pound can vary depending on the type of service chosen, the destination, and the package’s size. For example, USPS First-Class Mail charges less for lighter packages (up to 13 ounces), while heavier packages shipped through Priority Mail or Priority Mail Express are priced according to their weight and the destination zone.