Volumetric Shipping is a calculation many shipping providers use to determine the billable weight of a package. It uses both the package’s weight and density to determine the costs needed to ship your item to its destination.
How it Works
Volumetric weight, also known as Dimensional Weight, is a calculated number based solely on the dimensions of the box you are shipping. It reflects the package’s density, which is the amount of the space a package occupies in relation to its actual weight. This number is generally calculated by dividing or multiplying the volume of the package by a special number given by your carrier. The image below, taken from the UPS website, illustrates how volumetric shipping works when sending packages within the United States.
The volumetric number here is 166, and the volume of the package is divided by this value to obtain the dimensional weight. Let’s say you are shipping a 12″ x 8″ x 8″ box. The volume of this box is 768 inches squared. Dividing that value by 166 results in a volumetric weight of 4.63 pounds.
Table Rate & Volumetric Shipping
The volumetric weight is not always the weight value of the package. It’s primary purpose is to ensure that the shipping provider is compensated for both weight and density of the items you are shipping. After the dimensional weight is calculated, it is compared to the physical weight of the item. Whichever number is greater is the number that the shipping company uses as the package’s official weight.
The Table Rate shipping method is automatically setup to do just that, with very little effort on your part. When this feature is enabled, the volumetric weight will be calculated for each item in the cart using the dimensions you have provided. The calculated value will be compared to the weight you also provided in the product’s settings. The higher of the two numbers will then be used as the item’s weight value. So if you are charging for shipping based on the weight of an item, it is this new weight value that will be compared. This includes the Based On condition being set to Weight, as well as using the Cost option ‘w’, which multiplies the given price by the weight of the items.