The figure before the material
Square feet, cubic feet and cubic yards are where an order begins. These calculators take a length however it is written, in feet and inches, in yards or in metres, add several shapes together, and give the result in each unit a store or a supplier might ask for.
When the figure is for a material, the calculator of that material takes it from there: tons, bags and sheets are on its own page.
Updated . How we calculate. Found a mistake? Tell us.