About Lawn & Landscaping Calculations
Landscaping materials split into two camps: area goods like sod and seed, and bulk goods like soil and gravel sold by volume or weight. Sod comes in rolls or slabs that cover a set area, so you take your lawn's square footage, add about 5% for cuts around beds and curves, and round up to whole pieces. Order it for same-day install, because sod sitting on a pallet in the sun dies fast.
Soil, gravel, and mulch are volume problems. You measure the area and the depth you want, multiply to cubic feet, then convert to cubic yards since that's how it's delivered, where one cubic yard is 27 cubic feet. A 2-inch layer over a big bed adds up to more yards than people guess, so run it before you call the yard.
Gravel and stone often sell by the ton instead of the yard, and the two aren't interchangeable. You convert volume to weight through the material's density, and different stone weighs differently, so a yard of pea gravel isn't a ton of crushed rock. Grass seed goes by pounds per thousand square feet, and the rate depends on whether you're seeding bare ground or overseeding an existing lawn, so read the bag.
Pros run these numbers to order bulk material in one delivery and skip the second-trip fee. Figure your area, pick your depth, convert to yards or tons, and have it dropped once.