How does dimensional weight affect shipping costs?

Dimensional weight, often abbreviated as DIM weight, is a pricing technique used by shipping carriers, including USPS, to determine shipping costs based on the volume of a package rather than just its actual weight. This method is particularly important for lightweight but bulky packages, as it reflects the space a package occupies in relation to its weight.

When a package's dimensional weight is greater than its actual weight, the carrier charges based on the dimensional weight. This means that shipping costs can increase based on the size of the package, even if its actual weight is light. The use of dimensional weight helps carriers optimize their shipping methods and manage space efficiently on trucks and planes, ultimately reflecting in pricing.

This approach ensures that shippers are paying a fair rate for the space their packages occupy in transit. Therefore, the correct understanding is that dimensional weight increases shipping costs based on the size of the package.