Package delivery giant UPS on Tuesday said beginning Dec. 29, in the United States, dimensional weight will be used to calculate the billable weight of a shipment on all UPS Ground services and UPS Standard to Canada packages.

UPS already applies this method for UPS air services, domestic and international; UPS Standard to Mexico ground services; and for UPS Ground packages and UPS Standard to Canada packages measuring 3 cubic feet in size or larger.

"UPS has been researching the potential expansion of dimensional-weight pricing for a number of years because it enables us to more appropriately align rates with costs which are influenced by both the size and weight of packages," said Alan Gershenhorn, UPS executive vice president and chief commercial officer.

A similar move by rival FedEx was announced last month.

“Recent e-commerce shipping trends have resulted in a decrease of package density,” the company said. “For example, the package weight compared to the physical exterior dimension is declining. This trend causes cargo space to be less efficiently utilized, resulting in an increased cost per package.”

The company believes that as a result of the dimensional weight pricing method, more shippers will seek to optimize their packaging practices. “These efforts will reduce excess packaging materials and overall package sizes, leading to related reductions in fuel use, vehicle emissions and transportation costs,” said UPS