The Formula Behind This Calculator
Volume (cubic feet) = length (ft) x width (ft) x depth (in) / 12
Cubic yards = cubic feet / 27
Bags = round up (cubic feet / 1.5), Weight (tons) = cubic yards x 1.15
Soil is a volume product, whatever the project shape. The only trap in the arithmetic is mixing units, so everything converts to cubic feet first, then to the cubic yards bulk yards sell and the bag counts retail stores sell. The weight factor, about 1.15 tons per cubic yard, is the middle of the range for screened topsoil at garden moisture. Saturated soil can run a quarter heavier, which is worth remembering on delivery day if your truck, not theirs, is doing the hauling.
Worked Example: Topsoil for a 30 by 20 Garden Area
A homeowner is building up a 30 by 20 foot garden and lawn area with 4 inches of topsoil over tired native ground.
- Area: 30 x 20 = 600 square feet.
- Volume: 600 x 4 / 12 = 200 cubic feet.
- Cubic yards: 200 / 27 = 7.41 cubic yards.
- Bags: 200 / 1.5 = 133.3, so 134 bags if bought bagged.
- Weight: 7.41 x 1.15 = about 8.5 tons.
- Budget: bulk at $30 to $55 per yard gives $222 to $407 of soil, plus one delivery.
The example exposes the bag decision instantly: 134 bags is a pallet and a half, an afternoon of slitting and spreading, and roughly double the money. Under a yard, bags are convenience. At seven yards, bags are a penance. One bulk load, a wheelbarrow and a landscape rake turn this into a single Saturday.
A Complete Guide to Buying Topsoil
Topsoil sounds like a commodity and behaves like a local product. What a yard sells as topsoil is whatever was screened from land near you, which means quality ranges from rich dark loam to powdered subsoil with ambitions. This guide covers how much to buy, how to judge quality before seven yards of it are sitting on your driveway, and where the depth numbers come from.
Depth by Project
Depth is the decision everything multiplies from. Lawns want 2 to 4 inches over decent ground and 4 to 6 over construction subsoil or heavy clay. Garden beds want 6 to 8 inches of good material in total, counting what is already there and workable. Raised beds are filled to within 2 inches of the rim, usually 10 to 11 inches in a standard 12 inch bed. Grading and filling low spots is measured at the deepest point and feathered out: soil spread over existing lawn deeper than about an inch at a time will smother the grass beneath unless you intend exactly that. When in doubt between two depths, remember that soil settles 10 to 20 percent as it wets and compacts, and shallow roots are forever thirsty.
Judging Quality Before You Buy
Good topsoil is dark, crumbly, and smells like earth rather than chemicals or sour swamp. Ask the yard two questions: is it screened, and to what mesh? Screened to a half inch is the retail standard; unscreened soil carries rocks, roots and clods that you will pick out by hand for a season. If the project is a lawn, ask whether the soil is tested or amended, and be skeptical of soil that is suspiciously cheap: fill dirt sold as topsoil is the oldest trick in the bulk yard. For beds, many gardeners buy a topsoil and compost blend or plan to amend with compost at planting, since plain topsoil is a growing medium starter, not a finished garden soil.
Bulk Versus Bags, and Delivery Reality
The break even is roughly one cubic yard. Below it, bags win on handling, storage and zero delivery fees. Above it, bulk wins on price so decisively that the delivery fee barely matters. A delivered yard count also buys you a driver who can split the load or spot it close to the work area, which is worth hours of wheelbarrowing. Check access before ordering: a loaded dump truck needs height clearance, a firm surface, and will crack a weak driveway edge without blinking. Get the pile placed on a tarp or on the driveway side you can hose clean, and never on the lawn you are about to improve unless you plan to fix that patch too.
Timing and Settling
Order soil a few days ahead of your work window in spring, when yards sell out on weekends, and avoid delivery the day after heavy rain if the pile must sit: wet soil weighs more, spreads worse and compacts under its own water. Spread, rake, water lightly to settle, then top up the low spots before seed or sod. The calculator figure is the placed volume; if your project cannot tolerate a second trip, add 10 percent at the order line and keep the change for bed top ups. Soil, unlike most materials on this site, is never really wasted.
Ordering Day Checklist
Before you phone the yard: confirm whether their yard is a true 27 cubic foot scoop, because bucket sizes vary and short yards are an industry legend for a reason. Ask what the delivery minimum and fee are, whether the truck can split the load between two drop points, and where exactly it can safely dump on your property. Measure your gate and path widths for wheelbarrow access, or plan the pile location to minimize hauling distance, which is where the real labor lives in any soil project. And take the weather into the plan: spreading soil ahead of a gentle rain is ideal for settling, while a downpour on a fresh pile turns your driveway into a mud export business. A cubic yard covers a surprising amount of ground at lawn depths, so when your calculated number looks small against the size of the yard, trust the math and this checklist rather than the instinct to double the order.