All international carriers base their shipping rates on the greater of actual weight and dimensional weight (also known as volumetric weight).

Actual weight is the weight of the package when put on a scale. Dimensional weight is based on the size and weight of the package. Large items that have a low actual weight, like pillows and lampshades, will result in a higher dimensional weight. 

Dimensional weight is calculated by multiplying the dimensions of an item and dividing by the industry-standard "DIM Factor" of 139:

Dimensional Weight (chargeable pounds)  = Length x Width x Height (inches) / 139

Fortunately, MyUS members do not have to worry about complex dimensional weight calculations. MyUS TruePrice™  gives you guaranteed upfront pricing based only on the package weight (excludes oversized and pallet shipments).

Oversized packages, crates and pallets:

Oversized packages are packages or pallets with linear dimensions (total Length + Width + Height) greater than 72 inches (183 cm). Items requiring some types of special packaging (e.g. crates), are not eligible for MyUS TruePrice pricing.