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Shipping Costs

But the scale says 5 lbs!

By November 9, 2018December 9th, 2020No Comments

Dimensional weight and its effect on shipment cost

If you haven’t had the pleasure of shipping a package recently, you are probably unfamiliar with the term “dimensional weight.”  This is a big fancy term that our friends at UPS, FedEx, USPS (and every other parcel carrier) use to describe the weight of an item based on how big it is.  That’s right folks, the scale is no longer the only thing you have to worry about.

Several years ago, all of the shipping carriers implemented dimensional weight, and it was put in place to charge you more for packages that take up lots of space in their trucks.  This is a really big deal for customers who ship bulky items; however, it affects nearly all shipments and can easily add significant costs. All carriers base their rates on weight and distance (zones); having a large dimensional weight means you pay more for the shipment.

Okay, enough of the history lesson. This is how it works. The carriers compare the actual weight of your package to the dimensional weight and charge you based on whichever is larger! The impact can be significant; a 2 pound box that used to cost $10.00 to ship might cost $20.00–30.00 when you use the dimensional weight. To calculate dimensional weight, follow the below steps:

  • Measure the dimensions of your package and round each number up to the nearest inch.
  • Multiply those three numbers together and divide by the divisor provided by your carrier. The divisor starts at 139, most companies have 160 or 166. NOTE: The divisor is a key element to this. It is a negotiable number and a good fulfillment partner will have a higher number…resulting in a lower rate.
  • Round the result up to the nearest number…that is the dimensional weight of your package.  Now compare the two weights and lookup the cost difference to ship…wow.

Wait…I have to do math?  If you prefer not to crunch the numbers yourself, check out our dimensional weight calculator and test a few examples. After you see the standard result, press the “See SI Fulfillment’s Weight” button to see how working with us can help you save on shipping costs.


What is it?
Dimensional weight is a calculation that factors not only the weight of an item, but its length, width, and height to determine the cost of a shipment.

Why does it matter?
If you are asking this question, you don’t ship large items!  Dimensional weight is a really big deal because a large box that only weighs 2 pounds can be charged as if it weighs 30 pounds!  That is a HUGE price difference.

How do you calculate dimensional weight?
To calculate dimensional weight, measure the length, width, and height of your box.  Round each measurement to the nearest whole inch (Example:  10.5 = 11 inches).  Multiple those three numbers and divide by the denominator provided by your carrier.

What can I do to reduce dimensional weight?
Before you panic or decide to only ship small, light items…there are a few ways to try and reduce the impact of dimensional weight.

  1. Right size your package – make sure you choose the smallest box possible for the product inside. This is one of the most effective methods to lower your shipping costs.  Even if it spend a little more on packaging, it will likely still save you money on freight.
  2. Flat rate package services – most carriers have introduced flat rate shipment boxes…if it fits in the box it ships for a fixed rate!
  3. Find out what your fulfillment company uses as a denominator for package weight.  It is a poorly kept secret that this can be negotiated!  A fulfillment partner with good shipment volume is likely to have a denominator larger than 160…resulting in lower dimensional weights.

Partnering with a fulfillment business who understands the above will provide significant savings to your shipping costs.  Please contact us if you want to learn more about how SI Fulfillment can lower your shipping costs.