Press Save to my list under any calculator and the result appears here, so you can plan a whole project (the concrete, the gravel and the rebar, say) and print or copy one list. It is kept in this browser only. We never see it, and clearing your browser data removes it.
Your list is empty. Open a calculator, enter your numbers and press Save to my list. Good places to start: concrete, paint, gravel, deck boards or the UK calculators.