Dimensional weight, also known as dim weight or volumetric weight, is a pricing technique used by shipping carriers to calculate shipping charges based on the package's size rather than its actual weight. It helps account for the space a package occupies in the carrier's transportation vehicles, as larger, bulkier packages take up more room and reduce the carrier's capacity to transport other packages.

The dimensional weight is calculated by comparing the package's actual weight to its dimensional size. The higher of the two values, the actual weight or dimensional weight, is used to determine the shipping cost.

To calculate dimensional weight, the following steps are typically involved:

Measure the length, width, and height of the package in inches. Ensure you use the outermost points of the package, including any bulges or irregular shapes.

Multiply the length, width, and height measurements together to obtain the package's total volume in cubic inches.

Different shipping carriers use specific dimensional factors to convert volume into dimensional weight. The dimensional factor is a constant number that represents how many cubic inches equal one unit of weight (e.g., pounds or kilograms). The dimensional factor may vary depending on the carrier and the unit of weight used.

Compare the package's actual weight (in pounds or kilograms) to the dimensional weight (also in pounds or kilograms) calculated in the previous step. The higher of the two values is used to determine the shipping cost.

Dimensional Weight = (Length x Width x Height) / Dimensional Factor

It's important to note that dimensional weight calculations may differ slightly between carriers, as they can have varying dimensional factors and rules. Some carriers may apply additional adjustments or surcharges based on specific package characteristics or shipping services.