Having trouble calculating shipping costs? Use this handy set of tools as a starting point. They can help convert between imperial and metric units and calculate the all-important freight density. Also known as dimensional weight or cargo density, freight density is a measurement of how much weight is concentrated into an area of volume. Remember that billable weight is the greater of an item's dimensional weight or actual weight. Lighter or more fragile objects that take up more space can be more costly to ship than heavier objects that take up less space!