Why stack weight matters
On a container ship, each bay and tier has a maximum stack weight printed in the cargo securing manual. If the total weight of boxes in one stack exceeds that limit, the hatch cover, tank top or lashing bridges can be overloaded. Heavy containers should normally sit lower in the stack, and the planner must also keep the stack within the allowed height and lashing capacity.
How this calculator works
If you know the exact total weight, enter it in the “known stack weight” box. Otherwise enter the number of containers and an average weight. Total = count × average, or the known total. Margin = Maximum allowed − Total. A negative margin means the stack is overweight and the stow must be changed. This is a planning check only. Official stowage must follow the CSM, VGM figures and the loading computer.
Who should use it
Useful for chief officers and planners doing a quick check before loading. Always use verified VGM weights, not estimated weights, for the final plan.