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Understanding Purolator’s Dimensional Weight: How it Impacts Your Shipping Costs


Imagine this: you’re excitedly packing up a gift for a friend, ready to ship it across the country. You drop it off at the shipping counter, expecting a reasonable price. But then, you’re hit with a sticker shock – the cost is significantly higher than you anticipated. This, unfortunately, is a common experience for many, and it often stems from something called dimensional weight.

Dimensional weight, in a nutshell, is a way shipping carriers like Purolator calculate shipping costs based on the size and volume of your package, not just its actual weight. This seemingly complex concept can dramatically impact your shipping expenses, especially when dealing with larger or bulky items.

This blog post aims to demystify Purolator’s dimensional weight calculation and its influence on your shipping costs. We’ll walk you through the formula, provide practical tips for optimizing your packages, and answer frequently asked questions about this critical aspect of shipping.

Table of Contents

  1. What is Dimensional Weight?
  2. Purolator’s Dimensional Weight Calculation
  3. How Dimensional Weight Affects Your Shipping Costs
  4. Understanding Your Purolator Invoice
  5. Optimizing Your Packages for Dimensional Weight
  6. Frequently Asked Questions
  7. Conclusion
  8. Resources

What is Dimensional Weight?

Dimensional weight, sometimes referred to as volumetric weight, is a way shipping carriers calculate shipping costs based on the space your package occupies in transit, rather than solely its actual weight. This concept arises because shipping a large, lightweight package takes up as much space as a smaller, heavier package. To account for this, carriers use a formula to calculate dimensional weight.

Why Do Carriers Use Dimensional Weight?

Shipping companies use dimensional weight to ensure fairness in their pricing. If they only considered actual weight, they might end up losing money on shipments that occupy a lot of space, even if they’re relatively lightweight. Dimensional weight helps balance the costs associated with transporting large packages.


Imagine you have a package that measures 20″ x 15″ x 10″ and weighs 5 pounds. You might think that the actual weight (5 pounds) is the primary factor determining your shipping cost. However, the dimensional weight of this package could be significantly higher due to its size.

Purolator’s Dimensional Weight Calculation

Purolator uses a specific formula to calculate dimensional weight:

Dimensional Weight = (Length x Width x Height) / Divisor

Here’s a breakdown of the formula:

  • Length, Width, and Height: These dimensions are measured in inches.
  • Divisor: Purolator uses a divisor of 194 for calculating dimensional weight.


Let’s consider a package with dimensions of 20″ x 15″ x 10″. Using the formula above:

  • Dimensional Weight = (20 x 15 x 10) / 194 = 15.51 lbs

Notice that even though the actual weight of the package might be less than 15.51 lbs, Purolator would base the shipping cost on the higher dimensional weight.

How Dimensional Weight Affects Your Shipping Costs

Purolator uses the higher of the two weights – actual weight or dimensional weight – to calculate your shipping costs. In the example above, if the package weighed 10 lbs, the shipping cost would still be calculated based on the 15.51 lbs dimensional weight.


Imagine you have two packages:

  • Package A: Actual Weight: 10 lbs, Dimensions: 15″ x 12″ x 8″
  • Package B: Actual Weight: 5 lbs, Dimensions: 24″ x 18″ x 12″

Let’s calculate the dimensional weight for each package:

  • Package A: (15 x 12 x 8) / 194 = 9.34 lbs
  • Package B: (24 x 18 x 12) / 194 = 26.79 lbs

In this scenario, even though Package A is heavier, Package B has a significantly higher dimensional weight. As a result, Purolator would likely charge a higher shipping cost for Package B, despite its lower actual weight.

Impact on Businesses:

For businesses, especially those shipping large or bulky items, understanding dimensional weight is crucial. It can significantly influence your bottom line, and you need to factor it into your pricing and shipping strategies.

Understanding Your Purolator Invoice

When you receive your Purolator invoice, you’ll find information about both actual weight and dimensional weight. This information helps you understand how the shipping cost was calculated.

  • Identifying Dimensional Weight: Look for a line item on your invoice that states “Dimensional Weight” or “Volumetric Weight.”
  • Cost Breakdown: The invoice should clearly display the cost breakdown, including charges based on actual weight and dimensional weight.

Addressing Discrepancies: If you notice any discrepancies or inconsistencies related to dimensional weight on your invoice, contact Purolator’s customer support. They can help clarify the calculations and address any concerns you might have.

Optimizing Your Packages for Dimensional Weight

Now that you understand how dimensional weight impacts your shipping costs, let’s explore ways to optimize your packages to minimize these costs.

Package Selection:

  • Choose the Right Size: Opt for boxes that fit your items snugly with minimal wasted space. Selecting a box that is too large can dramatically increase dimensional weight.
  • Consider Alternatives: If possible, explore using alternative packaging options like poly mailers, envelopes, or tubes for smaller items. These can significantly reduce dimensional weight compared to traditional boxes.
  • Don’t Overpack: Avoid filling boxes with excessive packing materials. Use only enough to protect your items while minimizing the overall package volume.

Packaging Techniques:

  • Nestle and Stack: If you’re shipping multiple items, consider nesting smaller items inside larger ones to maximize space efficiency.
  • Use Dividers: Use cardboard or foam dividers to separate fragile items and prevent them from shifting, potentially increasing package dimensions.
  • Fold and Flatten: If possible, fold and flatten items before packing to reduce their overall height and volume.

Material Selection:

  • Lightweight Materials: Choose lightweight packaging materials like bubble wrap, packing peanuts, and corrugated cardboard. These materials provide adequate protection while keeping the package’s overall weight down.
  • Reusable Materials: Consider using reusable packaging materials like padded mailers or shipping boxes. This not only minimizes waste but can also save you money in the long run.

By following these tips, you can optimize your packages for dimensional weight, potentially reducing your shipping costs and improving your bottom line.

Frequently Asked Questions

What happens if my package’s dimensional weight is higher than its actual weight?

Purolator will use the higher of the two weights (actual weight or dimensional weight) to calculate your shipping cost.

How can I calculate dimensional weight myself before shipping?

You can use a dimensional weight calculator available online. Simply input the package dimensions (length, width, and height) and the calculator will determine the dimensional weight.

Does Purolator offer any discounts for lighter packages?

Purolator may offer discounts based on weight and volume, but these are typically not directly related to dimensional weight.

Can I negotiate dimensional weight charges with Purolator?

It is possible to negotiate dimensional weight charges with Purolator, especially if you are a high-volume shipper. However, this will depend on your shipping volume, contract terms, and individual negotiation skills.

What are the consequences of shipping a package with inaccurate dimensions?

If you provide inaccurate dimensions for your package, Purolator may charge you additional fees or penalties. They may also experience delays in processing your shipment due to discrepancies in the provided information.


Understanding dimensional weight is critical for anyone shipping with Purolator, especially for businesses. By understanding how it works and implementing the tips for optimizing your packages, you can reduce your shipping costs and improve your overall shipping efficiency. Remember to carefully measure your packages, choose appropriate packaging materials, and utilize efficient packing techniques. This knowledge will empower you to navigate the world of shipping with confidence and save money in the process.