Every product as a density factor to allow us to work our weights of product when you order. We sell by the cubic metre, but our trucks, your ute, your trailer and the like are limited by the carrying weight capacity typically. A cubic metre of 20mm drainage gravel will weigh more than 1.3 tonnes (depending on a few other variables – like moisture). Most single axle box trailers can only legally carry 350-450kg, less than half a cubic metre of 20mm drainage gravel. We can help and advise on this when you come in. If you need a lot more it is often more convenient and economical to just have us deliver for you.