Sometimes a shipping company will give you an estimate for air freight or ocean freight, and the weight they calculated looks higher than what you might have expected. This is particularly common for smaller packages that you may have weighed on a scale at your home or business. So why does this occur? Is the company taking advantage?

The answer lies in an understanding of dimensional weight.

The Three Dimensions of Dimensional Weight

When you place a package – or a palette for that matter – on a scale, you are determining the gross weight of that shipment irregardless of the size and shape of the packaging. However, most carriers apply a pricing structure based on dimensional weight, which is also known as volumetric weight. It uses an estimated weight calculated from the three dimensions of the package: the length, width and height. Here’s why:

Various carrier types, such as airline cargo holds and long-haul trailers have large capacities that are underutilized when shipping small packages. Perhaps you placed a heavy, but relatively small and fragile item in a large box, surrounding the item with lightweight protective filler to keep it safe in transit. That’s smart packing. However, it also takes up room that could be used for other cargo.

For example, a trailer that can carry 45,000 pounds in freight by weight may only be able to fit 25,000 pounds of freight by volume when filled with many smaller sized packages. Because shipping companies need to maximize the efficiency of their operations, dimensional weight provides a more accurate reflection of both the space and weight, or density, of a package. Your shipping rate, then, is partially based on how much capacity it consumes. However, under the same principles of efficiency, some carriers may use the actual weight when it exceeds the dimensional weight of a package or container. This is because a carrier is also unable to fill a trailer or cargo area when a smaller number of heavy items prohibit more items from being loaded because weight limits are reached, even if there is physical space available for more items.

Your shipping company will help you determine the dimensional weight of your packages or commercial cargo, and determine the best and most economical means of getting it to your intended destination. Formulas vary by method: for example air freight uses a measure of weight in pounds (or kilograms), and ocean freight uses an indication of volume measured in cubic feet (or cubic meters). We’ve provided you with some of the ways that dimensional weight is calculated below.

Shipments by Air or Ground

World Cargo assists customers in moving smaller loads by air freight and ground shipping. These shipping methods use dimensional weight calculated in pounds or kilograms. Many domestic and North American carriers like Air Canada Cargo, Canada Post, and UPS use a formula like this:

L x W x H (Inches) / 366 (International/Air) = Dimensional Weight (kg)
L x W x H (cm) / 6000 (Domestic/Ground) = Dimensional Weight (kg)
LxWxH (in) / 166 (Domestic/Ground) = Dimensional Weight (lbs.)

A similar calculation is used for determining the dimensional weight of international air freight shipments through carriers like DHL, FedEx, UPS and Canada Post:

L x W x H (Inches) / 366 (International/Air) = Dimensional Weight (kg)
L x W x H (cm) / 6,000 (International/Air) = Dimensional Weight (kg)
LxWxH/139 (International/Air) = Dimensional Weight (lbs.)

Package sizes are rounded up to the next full inch, and weights are always rounded up to the next full pound / KG for pricing purposes. Carriers may compare dimensional weight to gross weight and apply the higher weight for pricing purposes.

Dimensional Volume is measured inclusive of the most outer measurements of the exterior packaging materials. Whether that be, a cardboard box, the pallet that the shipment is stacked on or a crate protecting the shipment. Furthermore, if the goods will be stacked onto a pallet; there may be void space in between the pieces if they do not stack well together. This will add to the overall dimensional volume (if you have measured the boxes individually). For this reason, we always recommend using like sized boxes for uniform stacking when possible.

Shipments by Sea

When shipping via ocean freight, weight calculations are also based on volume weight unless the gross weight is higher. Because ocean freight uses multiple 20’ and 40’ containers rather than a single trailer or cargo area, dimensional weights are calculated in cubic feet or cubic meters, like this:

L x W x H (in inches) / 1728 = Dimensional Weight (cubic feet)
L x W x H (in cm) / 1,000,000 = Dimensional Weight (cubic meters)

For purposes of comparison, there are approximately 35 cubic feet to one cubic meter, and for each cubic foot, the cubic weight is 10 lbs.

Leave the Math to Us

Wherever you want to ship your luggage, a motorcycle, palletized goods, a full container, or any other personal or commercial items, World Cargo will help you to navigate the challenges of moving them by land, sea and air. As a respected and experienced freight forwarder, we’ll do the measuring and the heavy lifting to ensure you receive the most accurate estimates and best possible service from the point of origin to the final destination. Contact us at 877-232-0204 or using our online form.