Every landscaping material is planned by area or by volume. Area is length × width in square feet; volume is the area × the depth in feet, divided by 27 for cubic yards. A 10 × 12 ft bed with 3 inches of mulch is 120 × 0.25 ÷ 27 = 1.1 cubic yards.
Stone, sand and soil are then sold by weight, so each calculator multiplies the cubic yards by a sourced weight per yard: about 1.4 tons for crushed stone and 1.35 tons for dry sand or topsoil. Sod is counted in square feet per pallet, grass seed in pounds per 1,000 sq ft, pavers per square foot, and pools in gallons.
The numbers behind the defaults come from university extension services, the ICPI for pavers, the CPSC for playgrounds, the American Wood Council for decks, NIST for units and manufacturers' data sheets. Each page names its sources, and you can replace any default with your supplier's figure.
For homeowners and landscaping contractors
Homeowners use a landscape calculator to order the right amount the first time. Landscaping contractors use them for quick takeoffs: add the client's name and download the PDF report to attach to a quote.
