Container Load Calculator

Max Cartons That Fit is the smaller of Max by Volume and Max by Weight. At lighter carton weights, Max by Volume is usually the binding constraint, so Carton Weight has room to increase without ever becoming the limiting factor. Only once Max by Weight drops below Max by Volume does raising Carton Weight start reducing the overall count -- the calculator switches constraints exactly at that crossover.

It depends on how evenly each carton dimension divides into the matching container dimension, since the packing math floors each division to a whole number before multiplying -- a carton dimension that leaves a large remainder wastes more usable container space than one that divides in cleanly. There is no single dimension that always matters most; it shifts with the specific carton size, container type, and how each dimension pairs against its matching container dimension.

Max by Volume is how many cartons physically fit based on dimensions alone, assuming perfect grid stacking with no wasted space. Max by Weight is how many cartons the container's payload rating can carry regardless of how much room is left. Shippers of dense goods like books or metal parts often hit the weight limit first; shippers of bulky, light goods like foam or apparel usually hit the volume limit first.

No. A 40ft container is not simply twice a 20ft container in every dimension -- length roughly doubles, but width and height are unchanged between the 20ft and 40ft standard options, and the 40ft High Cube option only adds interior height. Because the packing math floors each dimension's division separately, a small height or width change can shift how many cartons fit in ways that are not proportional to the container's total volume.