How much topsoil do I need?
One formula answers it: square feet × inches of depth ÷ 324 = cubic yards. The 324 is not magic — a cubic yard is 27 cubic feet, and spread one inch thick it covers 27 × 12 = 324 square feet. Everything else is choosing the right depth for the job, which is where most topsoil orders go wrong.
Pick the depth first
- New lawn (seed or sod): 4–6 inches of quality topsoil — the root zone that decides whether the lawn survives its first dry August.
- Topdressing an existing lawn: ¼–½ inch per pass, raked in. More than that smothers the grass you are trying to improve.
- Raised beds: 6–12 inches depending on crop — salad roots are shallow, tomatoes and brassicas want the full depth.
- Levelling low spots: the actual dip depth, plus a little for settlement — freshly placed soil settles noticeably in the first season.
Worked examples
- 1,000 ft² new lawn at 4 in: 1,000 × 4 ÷ 324 = 12.3 yd³
- 2,500 ft² lawn topdressed at ½ in: 2,500 × 0.5 ÷ 324 = 3.9 yd³
- Two 4 × 8 ft raised beds at 10 in: 64 × 10 ÷ 324 = 2 yd³
The cubic yard calculator runs this arithmetic with real soil weights attached, and thetopsoil calculator does the metric version with tonnes and bulk bags if you think in metres and millimetres.
What a yard of topsoil weighs — and why it matters
Dry soil is about 2,025 lb per cubic yard and wet soil 2,106 lb (the California waste board's published conversion figures), while screened topsoil as delivered — carrying normal moisture — converts to roughly2,516 lb per yard from Rolawn's ordering figure of one tonne per 0.67 m³. Two practical consequences. First, a modest 12-yard lawn order is around15 tons of material arriving on your drive — plan where the truck tips. Second, a half-yard scoop of damp topsoil already brushes the payload limit of many half-ton pickups; weight, not volume, is what stops you hauling it yourself.
Bags or bulk?
Bagged topsoil commonly comes in 0.75 or 1 cubic-foot bags — 36 or 27 bags to the cubic yard. For patching a few bare spots, bags win on convenience. For anything measured in yards, bulk delivery wins on price by a wide margin, and the comparison arithmetic is the same as for any bulk material: ourbulk-material cost guide shows how to put a per-bag price and a per-yard quote on the same footing before deciding.
Order a little over, not a little under
Topsoil settles after placement and rakes off unevenly, so the standard practice is a 5–10% allowance over the computed volume — the same waste-allowance logic our calculators build in. Coming up one yard short means paying a second delivery fee for the cheapest yard of soil you ever bought; the extra half yard from ordering generously top-dresses the lawn next season.
Frequently asked questions
How much topsoil do I need?
Multiply the area in square feet by the depth in inches, then divide by 324 — that is the square-feet-per-cubic-yard-at-one-inch constant (27 ft³ × 12). A 1,000 ft² lawn at 4 inches is 1,000 × 4 ÷ 324 ≈ 12.3 cubic yards. Typical depths: 4–6 inches for a new lawn, half an inch to an inch for topdressing, 6–12 inches for raised beds.
How much does a cubic yard of topsoil weigh?
Dry soil is about 2,025 lb per cubic yard and wet soil 2,106 lb, per the California waste board conversion table. Screened topsoil as actually delivered — with normal moisture — runs heavier: Rolawn's ordering figure (1 tonne ≈ 0.67 m³) converts to roughly 2,516 lb per cubic yard, about 1.26 US tons. Moisture is most of the spread, which is why topsoil quotes by weight vary with the weather.
How much is a yard of topsoil?
The price follows the same drivers as any bulk material: product quality (screened and blended loam costs more than unscreened fill soil), quantity, haul distance — usually the dominant cost — and whether it is tipped or placed. Regional prices vary too much for one honest number: compute your yards first, then price identical specifications with two or three local suppliers. Our bulk-material cost guide explains how to compare per-yard and per-ton quotes.
How many bags of topsoil make a cubic yard?
A cubic yard is 27 cubic feet, so it takes 36 bags at the common 0.75 cu ft size, or 27 one-cubic-foot bags. That arithmetic is the bags-versus-bulk decision in one line: beyond a few bags for spot repairs, a bulk yard delivered is nearly always cheaper per cubic foot and spares you three dozen cart trips.
What depth of topsoil does a new lawn need?
Four to six inches of quality topsoil is the standard recommendation for seeding or sodding a new lawn — enough root zone to hold moisture and nutrients. For topdressing an existing lawn, a quarter to half an inch per application is plenty; more risks smothering the grass. Raised vegetable beds want 6–12 inches depending on the crop.
What is the difference between topsoil, garden soil and fill dirt?
Topsoil is the screened upper layer of soil, sold for growing; garden soil is topsoil blended with compost or other organic matter for beds; fill dirt is subsoil — cheaper, denser, low in organic matter — used for raising grades and filling holes, not for planting. Never pay topsoil prices for fill, and never build a lawn on fill alone.
About these numbers
The soil weights come from the California waste board's volume-to-weight table and Rolawn's published ordering guidance, quoted verbatim on thematerial density reference and asserted in automated tests before any change to this site ships. The 324 constant is exact by definition. Supplier figures for your local soil win for your order — moisture and screening vary by yard and by week.