Dimensional weight, also known as volumetric weight, represents a pricing technique used in the air freight industry. It accounts for the space a package occupies in relation to its actual weight. This calculation often involves multiplying the length, width, and height of a package (in inches or centimeters) and then dividing by a dimensional factor, also known as a DIM divisor. For example, a box measuring 20 inches x 15 inches x 10 inches, when using a DIM divisor of 139, would have a dimensional weight of approximately 21.6 pounds (20 15 10 / 139). Carriers then compare this dimensional weight to the actual weight of the package, and the higher of the two is used to determine the shipping cost.
The adoption of dimensional weight pricing arose from the need to optimize cargo space utilization within aircraft. Historically, shipments were priced solely on their actual weight. However, light but bulky items could fill significant cargo space, preventing the shipment of heavier, denser goods. Implementing this pricing model ensures that carriers are compensated fairly for the volume occupied by a shipment, regardless of its actual weight. This incentivizes shippers to use more efficient packaging and potentially reduce overall shipping costs through optimization.