Updated 2022

DIM rules can change the way many online sellers do business, including how they charge for shipping, how they deliver packages to their customers, as well as repricing or even discontinuing certain products they sell if they don’t carry enough margin.

Below eFulfillment Service provides an explanation of how dimensional weight works, how it is impacting shipping costs, how the rules with the U.S. Postal Service differ from FedEx and DHL, and how you can estimate shipping rates as an online seller.

Definition of Dimensional Weight or DIM Weight: Dimensional weight, often called DIM weight for short, is a formula for evaluating the size of a package to determine shipping rates. Also called volumetric weight, shipping companies use dim weight to discourage larger lightweight packages because they take up so much room in the truck, yet at the low rate, they aren’t collecting enough fees. Here’s a good rule of thumb for ecommerce sellers to keep in mind when calculating dim weights: the shipping company will use whatever is heavier, actual weight or dim weight, because they make more money.

Dimensional Shipping for U.S. Postal Service, DHL and FedEx

Dimensional Shipping for the U.S. Postal Service and DHL

Both the U.S. Postal Service (USPS) and DHL use a dimensional weight factor of 166.

Calculating DIM Weight For DHL

DHL uses dim weight for international shipments, so if one is shipping inside the US, dim weight rules don’t apply to DHL shipments. However, dim weight does apply when one is shipping from the US to any country outside its boarders, including Canada, Mexico and the rest of the world (ROW).

When working with box sizes, DHL rounds every inch to the nearest whole inch. So, a box with dimensions of 30.4”(L) x 19.6”(W) x 19.5”(H), will be considered to be 30”(L) x 20”(W) x 20”(H) = 12,000 cubic inches.

Divide the total cubic inches by 166. Our example box of 30.4”(L) x 19.6”(W) x 19.5”(H), rounded up to 30”(L) x 20”(W) x 20”(H) = 12,000 cubic inches/ 166 is 72.28 lbs. Round up to the nearest pound for a dim weight of 73 lbs.

  • If the actual weight of that box is less than 73 lbs., DHL charges shipping based upon the DIM weight of 73 lbs.
  • If the actual weight of that box is more than 73 lbs., DHL will use the higher weight to figure the shipping rate.

Calculating DIM Weight For the USPS

For the USPS, dimensional weight applies when your package meets the following conditions:

  • Package is larger than one cubic foot, or 1728 cu. inches.
  • Shipping to any zone

USPS DIM Weight Hint: Do you use eFulfillment’s stock packages?

All the A packages are under 1 cu. ft and B2, B5 and B7 are also under a cubic foot. The rest of the B packages and all of the F packages are bigger than 1 cu. ft., and will fall under dim weight parameters for the USPS.


 

The calculations for USPS are the same as DHL, since they use the same rounding practices and divisor of 166.

Repeating our example from above, round up the dimensions of the package to the nearest inch.

So, a box with dimensions of 30.4”(L) x 19.6”(W) x 19.5”(H), will be considered to be 30”(L) x 20”(W) x 20”(H) = 12,000 cubic inches.

Divide the total cubic inches by 166. Our example box of 30.4”(L) x 19.6”(W) x 19.5”(H), rounded up to 30”(L) x 20”(W) x 20”(H) = 12,000 cubic inches/ 166 is 72.28 lbs. Round up to the nearest pound for a dim weight of 73 lbs.

  • If the actual weight of that box is less than 73 lbs., USPS charges shipping based upon the DIM weight of 73 lbs.
  • If the actual weight of that box is more than 73 lbs., USPS will use the higher weight to figure the shipping rate.

DIM Weight for FedEx

FedEx applies dimensional weight parameters to all packages using a factor of 139. When shipping with FedEx, always use the weight that’s higher between DIM weight or actual weight.

The formula for FedEx is the same, but one needs to divide by 139. And FedEx rounds the size to the nearest whole inch, rounding up for a half inch or above.

eFulfillment Service clients benefit from a better FedEx divisor, and so light bulky packages will benefit from better rates—ask your account executive for more information on stock packaging and DIM rates.

Calculating DIM Weight for FedEx

Using our same example box, with dimensions of 30.4”(L) x 19.6”(W) x 19.5”(H), the rounding is the same and will be considered to be 30”(L) x 20”(W) x 20”(H) = 12,000 cubic inches.

Divide the total cubic inches of 12,000 cubic inches by 139, for a DIM weight of 86.33 pounds, rounded up again to 87 lbs.

  • For FedEx, if the actual weight of that box is less than 87 lbs., FedEx charges shipping based upon the DIM weight of 87 lbs.
  • For FedEx, if the actual weight of that box is more than 87 lbs., FedEx will use the higher weight to figure the shipping rate.

An Easy Solution For DIM Weight Challenges

If the prospect of figuring out each shipper’s DIM weight for every package and comparing weights and rates to find the cheapest way to ship an order sounds like a pain, you’re right. eFulfillment Service clients can take advantage of our Best Rate Shipping Service, which automatically chooses the most economical shipper and service for the size, weight and destination of your order.

Additionally, our packing team balances efficient use of space and the right amount of protective packing for your order. We have a variety of box sizes and lightweight dunnage materials like bubble wrap, to ship ecommerce orders safely and economically. Sometimes an order can be packed in a safely in a box that is a little smaller, avoiding DIM weight issues altogether. Clients can focus on building their business, while leveraging eFulfillment Service’s shipping experience, our variety of materials, tools and technology.