Press Save to my project list under any calculator to add the result here, grouped by project with the quantities added up. Type a project name on an item to move it. The list stays in this browser (we never see it), and clearing your browser data removes it. Any cost rows come from the prices you typed, so check them at your builders' merchant.
Your project list is empty. Open a calculator, enter your numbers and press Save to my project list. Good places to start: concrete, paint, turf or the full list of UK calculators.