Results are estimates for planning and ordering. Real quantities vary with how material is loaded, how moist it is, how much it settles and how uneven your ground is. Confirm quantities and product weights with your supplier before you order.
Calculators that touch on structure, such as rebar, retaining walls and rafters, give quantities and lengths only. They do not design anything. Slab reinforcement, footing sizes, walls taller than a few feet, and rafter sizes and spacing depend on local building codes, loads and site conditions; check with your local building department or a licensed engineer.
Tile sizes, box coverage, grout coverage and carpet and wallpaper roll sizes vary by product; check your product’s label and the maker’s instructions. Stair carpet that comes loose is a tripping hazard.
Roofing figures follow the International Residential Code and the shingle makers’ instructions as published; your local code, wind and ice-barrier requirements, and your product’s warranty terms may ask for more. Roof work is a fall hazard.