Start with your carrier agreement
Dimensional weight is a pricing measure based on package dimensions. Use the divisor, units, measurement rules and billing conditions that apply to your carrier and service. Keep those terms with the shipment data used for the comparison.
Separate packing space from shipping dimensions
The internal container dimensions determine the space available for products. The external package dimensions are the relevant input when applying a carrier's dimensional pricing method. Keep both in the container record.
Explore another box
Use Optipacker to review which of your available containers can accommodate the products under the chosen packing constraints. Inspect the result and retain the gaps, protection and handling space the order needs.
A container change can affect packaging material and shipping dimensions together. Review the resulting package against the applicable carrier rules to understand the effect on its charge.
Compare with real shipments
Use representative orders and actual carrier terms. Record the original package, the proposed package, any material changes and the resulting billed amount. Include shipments for which another charge or minimum determines the price.
That comparison gives purchasing and fulfillment a common basis for deciding which box sizes belong in the catalog.
Explore container selection for e-commerce or review the API workflow.