Shipping packages seems like a simple concept: your package weighs a specific amount, so your shipping rates should reflect that, right? Unfortunately, there are other factors that need to be addressed when preparing your packages for delivery. Shippers also need to account for something called dimensional weight (DIM weight) when calculating the total cost.
DIM weight is the amount of space a package occupies in relation to its actual weight. For each shipment, you are charged based on the DIM weight or actual weight of the package—whichever is greater.
Before 2015, major shipping carriers had a simple method to calculate costs of shipping items. First, they considered the weight of the item, and second, the distance it needed to travel. Therefore, the increase in weight and distance directly affected the increased cost of shipping. However, major carriers have recently added a third factor into their formula: the size (dimensions) of the item.
If you are shipping a lightweight item in an oversized box, the oversized box takes away valuable storage space in transit. Because of this, we see the need for DIM pricing, which considers the dimensions of item in the package. The classic example of a low-weight, high-volume shipment is a box of ping pong balls — they take up a disproportionate amount of space for their overall light weight.
Freight carriers like USPS, FedEx, or UPS calculate shipping charges based on whichever number is greater: the actual weight of the package or its calculated DIM weight. Whichever is higher becomes your billable weight.
Calculating DIM Weight
To calculate DIM weight, multiply the length, width, and height of a package, using the longest point on each side.
These measurements should include any bulges or misshapen sides, as irregularities can incur special handling fees if not incorporated into the calculating process of DIM weight.
Further, when calculating DIM weight, most shipping carriers ask that you round up to the nearest whole number.
Next, multiply those package dimensions to get the cubic size of the package. For example, if your package is 12 inches by 12 inches by 12 inches, your package size is the product of these three multiplied dimensions: 1,728 cubic inches.
In the end, the cubic size of the package is divided by a dimensional factor, also known as the DIM divisor. This is a number set by major freight carriers (UPS, FedEx, etc.) which refers to the total of cubic inches per pound.
The current DIM divisor used by FedEx for both domestic and international shipments is 139 cubic inches per pound. Using our example above, you would divide 1,728 by 139 to get a dimensional weight of 13 cubic inches per pound. Here is how a shipping carrier would determine the total cost of the package:
If the actual weight of the package is less than 13 cubic inches per pound (e.g., 11 pounds), the freight carrier will charge for the dimensional weight of 13 pounds since it is the greater number.
If the actual weight of the package is more than 13 cubic inches per pound (e.g., 15 pounds), dimensional weight pricing will be based on the actual weight.
At ShipSage, we can provide you with a DIM divisor that can benefit your shipping costs. Our negotiated DIM divisor is 285 cubic inches per pound. Using the numerical example from above, 1,728 cubic inches divided by 285 is 6 cubic inches per pound. Here is how ShipSage’s calculates DIM weight for our freight:
If the actual weight of the package is less than 6 cubic inches per pound (e.g., 4 pounds), the freight carrier will charge for the dimensional weight of 6 pounds since it is the greater number.
If the actual weight of the package is more than 6 cubic inches per pound (e.g., 8 pounds), dimensional weight pricing will be based on the actual weight, not the dimensional weight, since they charge for the greater number.
After the weight has been calculated, it is labeled in-house and ready to be transported.
With every dimensional element considered, shipping should seem less daunting. Furthermore, evaluating compatibility between your business needs and a fulfillment company is less stressful when you know what exactly factors into the overall shipping cost. ShipSage’s end-to-end process is simple, speedy, and scalable. We always strive to adapt to the seller in a way that maximizes their profit and grows their business. Shipping costs don’t have to leave you hanging high and dry. Leave your fulfillment to us!