Have you ever shipped a large box that seems to weigh nothing, yet the invoice you get is higher than you expected? This likely has to do with the difference between dimensional weight and actual weight. We all know how to find the actual weight of our international packages; we just look at the scale the box is sitting on and read the number. But why does my 10 lb shipment in a 12x12x12 inch box cost less than those same 10 lbs in a 24x24x24 inch box?

What is Actual Weight:

When you place a package (with contents included inside) on a scale, and it returns the weight of that package in pounds (or kilograms), that is the actual weight of the package. 

What is Dimensional Weight:

One can rightly assume that the box size has something to do with it, but what exactly? The term “Dimensional Weight” (or volumetric weight) is used to describe a box’s volume in relative pounds, which means a formula is used to convert its volume to pounds. That is then compared to the actual weight of the box that you see on the scale. It is an industry standard to bill a shipment by the highest weight; either actual or dimensional.

Dimensional Weight Formula:

The formula to calculate the dimensional weight for an international shipments is:

The dimensional weight formula for domestic shipments is similar, but with a different divisor. Typically, the divisor is 166, but it can vary by carrier. 

Why Are Shipments Billed at the Higher Weight?

Imagine a down comforter that weighs perhaps 10 pounds in a 24x24x24 inch box. You are not paying for the weight of that box; you are paying for the space it takes up in the airplane. In air shipping, we aren’t concerned with how much weight a plane can carry because, quite honestly, planes can carry thousands of pounds; we are concerned with the amount of space available. If you compressed that same down comforter and fit it into 12x18x6 inch box, your price drops dramatically because you are taking up less space, thus allowing the plane to take on more shipments.

Actual vs. Dimensional

To put it simply: actual weight is how much a package weights in pounds or kilograms, and dimensional weight (or volumetric weight) is how much space a package takes up. 

How to use this to your benefit:

The main takeaway is this: if you can ship your package in a smaller box, DO IT!

Be aware of the amount of space your shipment will take up and try to waste as little space as possible when packaging your shipments. Knowledge is power and understanding how your box size can affect your bottom line,  will make you a more efficient international shipper.