Assign a Package to Shipments based on Weight - Shipping Rules

Many carrier services use package dimensions to determine shipping costs. This method uses the length, width, and height of the package to calculate a "dimensional weight", also called DIM weight. When the DIM weight is greater than the actual weight of the shipment, then the DIM weight is used to find the postage cost. While each carrier calculates DIM weight using their own formula, merchants can reduce postage costs by optimizing packaging. Learn more about DIM weight.

A Strategy to Manage DIM Weight Shipments

The first step to lessening the effects of DIM weight is to optimize packaging. Your goal is to use the smallest sized package possible that will still safely protect your products during shipment. Learn about package optimization.

Once you have optimized your packaging, ShippingEasy can help automate your shipping selections. By knowing the DIM weight of each package type you use, you can attempt to use packaging with a DIM weight that is less than the actual shipment weight. This helps you manage postage costs, will save you time, and reduce human error as you select the best carrier service and packaging for each order.

The Plan to Set Up Your ShippingEasy Account

  1. Save custom packaging: add each package type that you use to your PACKAGE SETUP settings. This allows you to combine your package types with carrier services, as Shipping Presets. It can be helpful to include the carrier's DIM weight in the package name to more easily match the package with the shipping weight. Read the package set up guide

  2. Set up Shipping Presets: save combinations of the carriers, services, and packaging types that you use most often. This will make it possible to automatically assign these carrier selections to your orders, via Shipping Rules. As with package setup, it can be helpful to include the DIM weight in the Shipping Preset name. Read the Shipping Preset set up guide.

  3. Create Shipping Rules for each Shipping Preset: tell ShippingEasy which Shipping Preset you want to be assigned by default to your orders, based on their weight. This is where it will help to know the DIM weight of each package so that you can configure the Shipping Rules to look for shipments that are actually heavier than the DIM weight. 

  4. Organize your Shipping Rules: if you have more than one Shipping Preset, you will probably have more than one Shipping Rule. It matters how they are organized so that you are assigning the smallest package possible to your orders.

An Example to Describe this Rule

Now we want to set up a Shipping Rule that applies this to orders that weigh 10 lbs. or greater. That way, we can use optimally sized packaging for our heavier shipments and avoid paying a premium for package volume.


This rule is meant to optimize the carrier selections that you make for your DIM weight qualifying shipments. Each carrier has its own rules that govern DIM weight. For instance, USPS only assesses DIM weight on packages greater than 1 cubic foot, and only for specific services. Learn how to find the DIM weight for each carrier.

While the principals outlined in this rule can be applied to many package types, it has been optimized for DIM weight qualifying packaging and carrier services.

  1. For example, "Assign package w/ DIM weight 10lb".

  2. Set the "IF" condition to Order weight and select the logic being applied and enter in the specified weight diameters.

    if the order weight is greater than or equal to
    • Order weight | Is greater than or equal to | enter the DIM weight of the package

    In our rule, we set the Order weight to 10 lb.

  3. Since this rule will assign a specific Shipping Preset, it is best to set the destination as well. The destination should match the Shipping Preset. Add another condition for Destination | Is equal to | select the destination that matches the Shipping Preset.

    if the destination is equal to domestic

    For our example, we set the Destination to Domestic.


    If you would like to further qualify your orders, you may set more than one condition. For instance, if you use certain carriers based on the requested service, this will affect which Shipping Preset you assign. [View a complete list of available conditions.]

  4. Set the "THEN" action to Set shipping preset | select your shipping preset from the list provided.

    then set shipping preset to USPS priority mail

    For our example, we set the shipping preset to 'USPS Priority Mail - 16x12x10 - 10lb'.

Once you have created one Shipping Rule, repeat these steps for each Shipping Preset that you created for your DIM weight packaging.

Organize Your Shipping Rules to Optimize Package Selections

After you have created the Shipping Rules, make sure that they are in the correct order.

Most merchants will prefer to organize this set with the rules assigning the greatest DIM weight packaging first, and the smallest DIM weight packaging last. This is because the Shipping Rules are applied to your orders from top to bottom, as displayed on the SHIPPING RULES SETUP page. The rules lower on the list will override the ones up top - and you want to be sure to use the smallest package possible.

  1. Arrange your Shipping Rules by clicking the arrow direction for each rule and place them in the order that you want them to be applied.

    Shipping Rules page showing action arrows to organize the shipping rule order highlighted


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