Volumetric Weight vs Actual Weight
To illustrate the difference between volumetric and actual weight, consider the following example. There are two boxes, each the same size. One is filled with golf balls and the other is filled with ping pong balls.
The box of golf balls would likely be charged by its actual weight while the box of ping pong balls would be charged by volumetric weight. Why? One box is heavier than the other, so they will be charged differently in shipping fees.
The box of ping pong balls takes up the same dimensional space as the golf balls, but because the box of ping pong balls is lighter, it’s a less efficient use of space. As a result, the box of ping pong balls will be charged by volumetric weight.