It’s time to use dimensions to calculate shipping emissions, not just the weight of an item

If dimensional pricing is used by DHL, UPS, FedEx by most carriers, why don’t we use dimensions to calculate carbon emissions too?

What I’ve come to realize is that since:

  1. The emissions difference between an empty and fully-loaded truck is only about 20 to 30%.
  2. The overwhelming majority of trucks in the US and I’m sure globally, cube out, i.e. run out of space, long before they hit their maximum weight limits.


  1. Item weight rarely makes that much of a difference on emissions, since 70 to 80% of the emissions come from the truck itself, not the cargo it’s hauling, e.g. the fuel consumed as a result of wind drag is the same whether the truck is fully loaded or not. 
  2. Space is almost always the primary constraint, not weight, so we should be allocating carbon emissions based primarily on cubic dimensions, not on just weight.

In order to more accurately allocate emissions, we should apply dimensional pricing to our carbon calculations. As a start we can use the 139 DIM divisor for inches or 5,000 for centimeters for both UPS and FedEx.

Given the rise of ecommerce and carbon taxes,  more accurately allocating emissions to the items being shipped  will be critical so that companies are both penalized and rewarded for minimizing the empty space in their packaging. 

Fortunately, carriers do use dimensional-weight pricing, which does encourage shippers to minimize package sizing.

Unfortunately, in the US, both UPS and FedEx regularly give their customers huge dimensional discounts, resulting in very few customers actually being  changed at the list rate, reducing the incentive for shippers to rightsize their packaging, but that’s a post for another day!

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