Dimensional Weight Based Shipping Rate Setup Guide

If you’re anything like us, you learn best by example. We have created a series of tutorials for our full suite of premium OpenCart shipping extensions to provide you with a better understanding of how to properly set up shipping rates for your OpenCart store.

We set up all rates using Advanced Shipping PRO (ASPRO), with the exception of the Per Product Shipping tutorial. If you are interested in one of our “lite” shipping extensions, the rate setup will follow the same format. To learn more about the difference between ASPRO and our “lite” shipping extensions, please review our Shipping Extension Cheat Sheet.

Table of Contents

Need help on a particular area? Select one of the following to go to that particular section.

What is Dimensional Weight?

Dimensional Weight takes into account the length, width, and height of each product. If the product’s Dimensional Weight is greater than the actual product weight, then the Dimensional Weight will be used to calculate the shipping cost. If the actual product weight is greater than the Dimensional Weight of the product, then the actual product weight is used instead.

Shipping Scenario

Harriet’s Hats sells a wide variety of men’s and women’s hats. From beanies to fedoras, they sell hats of all shapes and sizes. Most of the hats have very little weight to them, however, styles such as fedoras and sunhats cost more to ship due the size of the box required to maintain the hat’s shape during transit. Harriet has determined that she will calculate her shipping rates by Dimensional Weight, and her rates for North American will be as followed:

OpenCart volumetric weight shipping extension rate setup example

Why did Harriet decide to determine her shipping costs by Dimensional Weight instead of Weight? Well, in the case of the Classic Sun Hat which weighs .68 kg, if she were to determine the shipping cost by weight she would charge a rate of $7.99 to ship the hat the customer. Weight-based shipping does not take into account that the Classic Sun Hat needs to be shipped in a sturdy box that allows it to maintain its shape during transport. In this instance, the shipping courier would base their shipping cost on how much room the box would take up in their truck; the volumetric (dimensional) weight of the product. The volumetric weight is calculated by the (L x W x H) / Shipping Factor, so the Classic Sunhat’s volumetric weight would be 2.17 kg and would cost $12.99 to ship.

How Harriet Set Up Her Rates

General Settings

For the General settings, Harriet set her Rate Description to “Standard Shipping” to help keep her rates organized. She set her rate to “Enabled” and left the other General settings as is to suit her needs.

An overview of the General settings in Advanced Shipping PRO

Checkout Display

Harriet will be shipping via UPS, so she has attached the UPS logo as her shipping image to give customers a more thorough checkout experience. Harriet contacted UPS to determine the typical delivery time frame and added it to the Shipping Instructions field, which will be visible while customers are selecting a shipping option.

The Checkout Display settings allow you to add shipping information and a custom shipping image with your rates


As this shipping rate is only available to Harriet’s Hats North American customers, Harriet has ensured that she only selected North America in her Geo Zones.

Control which stores, customers, and geozones have access to a shipping rate

Shipping Calculation

Harriet is using ASPRO, so she selected Cart Dimensional Weight from the Shipping Cost Based On drop down menu. If she had purchased Dimensional Weight Based Shipping PRO, the system would automatically calculate shipping based on Dimensional Weight. After contacting UPS, she has determined the Shipping Factor to be 5000 cm³/kg. She wants her Final Shipping Cost to be based on only the highest valid shipping rate bracket, so she set the Final Shipping Cost to single.

Advanced Shipping PRO combines all of our "lite" shipping extensions into one affordable extension.

Shipping Rates

As determined earlier, Harriet is charging $7.99 for orders up to 2 kg, $7.99 up to 4 kg, and $18.99 for orders that weigh 5 kg and over. Setting up your shipping rates can look intimidating at first glance, but it’s actually very simple. There are only 4 formulas to calculate shipping rates:

  1. Flat Rate – value:cost
  2. Percentage – value:cost(%)
  3. Per Unit – value:cost/per
  4. Shipping Rate Fee – Add fee to the end of the shipping rate formula i.e. value:cost+fee

For Harriet’s rates, any order 5 kg and over is charged $18.99. Instead of writing out every plausible cart volumetric weight, we used ~ to signify that anything 5kg and over will be charged $18.99.

An example of volumetric (dimensional weight) shipping rates


Assuming a customer had a cart Dimensional Weight of 3 kg, the following is what they will see when viewing their shipping options during checkout. We added an express shipping rate for the screen below to show how multiple shipping rates will display.

The customer display after the rates are set up in Advanced Shipping PRO

Per Product Shipping Integration

Harriet has noticed a trend in her OpenCart store; customers are obsessed with her toques. On average, customers are purchasing 2-3 toques per order. To take advantage of and encourage this trend, Harriet has negotiated a special rate with UPS for her toques. Since it’s compatible with Advanced Shipping PRO (ASPRO), Harriet has decided to set up her special toque shipping rate in Per Product Shipping (PPS). To learn how Harriet set up her special toque rates in Per Product Shipping, check out Part 2.


If there is an aspect of setting up shipping rates you are stuck on, please don’t hesitate to contact us or leave your question in the comments below.