Dimensional Packing


Dimensional Packing allows you to achieve more accurate Shipping Rates, especially when getting rates from Live Rate Carriers like UPS and FedEx or when using USPS Flat Rate boxes. In this doc we’ll cover what Dimensional Packing is, how it works in ShipperHQ, and how to enable these settings. While it’s nearly impossible to achieve 100% accuracy 100% of the time, with thoughtful configuration ShipperHQ makes it possible to achieve extremely high levels of accuracy.

Introduction to Dimensional Shipping

Carriers like UPS, FedEx, DHL, and others rate packages by a combination of factors. Aside from distance, the most significant is weight. However, they do not use actual package weight for all shipments but rather the greater of Actual Weight, also called Dead Weight, and Dimensional Weight, also called Volumetric Weight.

Dimensional Weight is determined by taking the volume of a package and dividing it by a dimensional divisor (the standard divisor is 139). The result is then compared with the Actual Weight and the higher of the two is used when determining the shipping rate. For example, an 11 in x 8 in x 9 in package with an Actual Weight of 4 lbs would actually be rated on its Dimensional Weight of 6 lbs ((11 x 8 x 9)/139 = 5.7 rounded up = 6).

Many Ecommerce Platforms lack support for accurate Dimensional Rating because they do not support dimensions natively meaning all shipments are rated on Actual Weight only. Or, they lack sophisticated Dimensional Shipping capabilities meaning they take dimensions into account but the dimensions used don’t reflect the actual packages to be shipped.

The ShipperHQ Dimensional Packing Feature supports both a base capability to determine expected packages to be used based on available packages and item dimensions. However, we go beyond the basics with the ability to set specific options for how products are packed based on their individual attributes, combinations of items in the cart, differences between Carriers, etc.

How Dimensional Packing works in ShipperHQ

  1. ShipperHQ’s core dimensional algorithm looks at the product dimensions set on the eCommerce platform
  2. ShipperHQ then looks at the packages you set up in ShipperHQ
  3. It works out the best package(s) to use based on that information
  4. ShipperHQ takes the packages worked out for the order and sends this to the carrier to ensure accurate rating. If using custom rating, ShipperHQ will use the information to set the rate based on what package is used.

We’ve described a number of scenarios in our help docs to help paint the picture of what Dimensional Packing can help you accomplish. Browse these knowledge base articles here.

On Magento or Zoey you’ll want to ensure you synchronize any new boxes/dimensional rule groups you create.

As many live rate carriers refer to the largest dimension as the length ShipperHQ will rotate the dimensions so that the length is the largest dimension. This does not affect rating, however, as the volumetric weight is based on the volume of the box.

Getting Started

Enabling Dimensional Packing

  1. Navigate to the Advanced Features tab of your dashboard, and toggle Dimensional Packing to enabled.
  2. Click the Settings icon to select carriers that will take into account Dimensional Packing and Boxes.

Simply by enabling the Dimensional Packing feature, we’ll begin calculating rates based on the products’ dimensional weight, instead of its dead weight. This small toggle will provide carriers with a more accurate picture of your products, and therefore return a more accurate rate to display in the cart. By adding Boxes to ShipperHQ, you can implement your own business logic and configure a strategy (all the while, increasing your rating accuracy).


For most merchants, Dimensional Packing in ShipperHQ needs three significant pieces of information to perform its calculations:

  1. The dimensions of your products (defined on your products in your eCommerce platform)
  2. The dimensions of the packages you use to ship your products (called Boxes in ShipperHQ parlance, but these may be whatever you use from envelopes to pallets)
  3. Identification of any products or groups of products that need to be handled specially (ShipperHQ calls these Packing Rule Groups)

Please note that if the platform does not automatically add a 0 for decimals lower than 1 then it should be prefixed. I.e.: “0.5”, rather than “.5” should be entered as a dimension.

Live Rate Carriers

Dimensional Packing for Live Rate carriers works by allowing ShipperHQ to workout on the fly the most efficient Box or Boxes to pack a customers order into based on the product dimensions you’ve defined on your products in your eCommerce platform and the Boxes you’ve defined in ShipperHQ. If you don’t use the same approach on all of your products, you can also use Packing Rules to set special handling for certain groups of products (see section below).

Once ShipperHQ has selected the best boxes based on what you’ve defined, it then makes a call out to the Carrier’s API with the package dimensions and weights as well as the basic information required to retrieve a quote from a carrier (i.e. origin and destination addresses, account number, account settings, etc.). Since the carrier is being provided with full package information, they are then able to return much more accurate rates than if they were provided with only shipment weight.

Custom Rate Carriers

Dimensional Shipping works differently for Custom Rate Carriers than it does for Live Rate carriers since you are setting the rate within ShipperHQ instead of calling out to a Carrier’s API to get the rate. More information is available in our Dimensional Shipping with User-Defined Rates document.

Dimensional Packing is not available for Free Shipping, In-Store Pickup, and Same Day Carriers.

The ShipperHQ Best Fit Dimensional Algorithm

This article describes how ShipperHQ packs products into boxes for Dimensional Packing when the packing algorithm is set to Best-Fit packing.

Packing Boxes

ShipperHQ first checks the individual dimensions of the products to ensure that the dimensions do not exceed the dimensions of the box. For example, a product that has dimensions of 5x3x12 cannot fit into a 10x10x10 box because one of the dimensions exceeds each of the dimensions of the box. The system does, however, attempt to rotate the box so that same product could fit into a 14x10x10 box, for example.

Next, the system takes the volume of the product(s) in the cart and compares that against each of the boxes that are eligible to be used for that product. So, for example, a 5x5x5 product has a volume of 125 so it can fit into any box that has a volume greater than 125 (after accounting for the individual dimensions, above). This denotes how many of that product can fit into each box and how much space is left over.

Lastly, the system checks to maximum weight and the maximum quantity for the boxes. This is defined in Box Definitions > (box name) > “Max Quantity Box can Hold” and “Max Weight Box can Hold”.

Note that the box tolerance/padding will have an effect on the volume of the products that can fit into a box.

If you are using Magento/Zoey you can also apply master packing boxes, which will be favoured over other packing boxes.

You can find a more detailed example on our packing examples page.


When attempting to pack, items for which no possible boxes are found will go into a fallback box (or boxes, as carrier package weight limits will be respected). This box will be called SHQ CUSTOM. The box will be the dimensions of the largest product with no box available and all boxless items will go into it for rating purposes, even if they logistically wouldn’t fit (while still respecting weight limits). There are some cases where this is desirable (such as taking the total weight of the cart and rating it as a single item with no dimensions to overcome package limits for an LTL carrier) but in general you will want to define enough boxes so that this SHQ CUSTOM box will not be used.

If you do not have the Dimensional Packing feature turned on, all items will go into these SHQ CUSTOM boxes as described above, but with no dimensions on the box or boxes (it will say 0x0x0).
(Additional boxes will be used when the carrier’s package weight limit is reached for a box.)

Further Reading

It is also possible to modify the products to pack specific quantities of products into boxes, as detailed in this article.

If you have a single product that ships in multiple products please see this article. This can be used if, for example, you have a table product where the table top ships in one box with its own dimensions and the legs ship in one or more boxes of a different size.

Options for Special Handling

In addition to the primary approach where ShipperHQ determines the most efficient box or boxes to use, you can also configure certain sets of products to be handled differently. These sets of products are called Dimensional Rule Groups in ShipperHQ. Packing Rules are defined in ShipperHQ and then applied on your products in your eCommerce platform so that ShipperHQ knows which products belong to which group.

The dimensional rule options available are for items which ship separately, items which ship in multiple fixed boxes, and items which can only ship in certain boxes. For detailed descriptions of these options and how to use them, please see the Packing Rules Configuration document.

On Magento you can optionally not use dimensional rule groups and just assign possible shipping boxes on a product level. You may also set a product to Malleable on Magento in which case ShipperHQ will consider only the volume, not the dimensions them selves when determining whether the product can be packed in a certain box.

Master Box Packing

On the Magento platform we have support for setting master packing boxes on your SKUs. So for instance you may sell wine and it packs in cases of 12, this is the master box, but you can also ship in individual qty. If the customer adds 14 of that SKU to the cart and there is a master box setup then it would pack 12 in the master box and the other 2 in the leftover box (taken from possible boxes).

More Information

For detailed descriptions of the individual features and how to enable them, please see our Packing Rules Configuration document.

You can find more information about the options available in our Packing Rules category.

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