How Much Topsoil Do I Need?
Topsoil is sold by volume, but the depth you spread it at drives the total. Get the area and depth right, add a little for settling, and you avoid both a thin, patchy lawn and a leftover mountain of soil.
Area times depth equals volume
Multiply the area in square feet by the depth in inches and divide by 12 to get cubic feet. Divide by 27 for cubic yards. A 200 square foot strip topped with 4 inches of topsoil needs 200 × (4 ÷ 12) = 66.7 cubic feet, or 2.47 cubic yards. Add a waste allowance for settling and uneven ground before you order.
Choose depth by purpose
| Use | Typical depth |
|---|---|
| Lawn topdressing | 0.25–0.5 in |
| Repairing bare patches | 1–2 in |
| New lawn over existing soil | 4–6 in |
| Raised bed or new garden bed | 6–12 in |
A thin topdressing evens out a lawn and improves the surface without smothering grass. A new lawn or garden bed needs enough depth for roots to establish. For dedicated raised beds, use the Raised Bed Soil Calculator and read How Much Soil Does a Raised Garden Bed Need?
Account for settling and uneven ground
Loose topsoil settles after the first few waterings and rains, often by 10 to 20%. Few lawns or beds are perfectly flat, either — low spots quietly absorb more than the calculation suggests. A 5 to 10% allowance covers typical settling; sloped or rutted ground may need more. It is easier to spread a little extra than to match a new delivery to the existing soil.
Bags or bulk?
Bagged topsoil is convenient for small beds and spot repairs. A 2 cubic foot bag covers 24 square feet at 1 inch, so a cubic yard (27 cubic feet) equals about 14 bags. For larger projects, bulk topsoil by the yard is usually cheaper and means fewer trips. For a full comparison, see Bulk Topsoil vs. Bagged Soil.
Worked example
A 20 by 10 foot lawn strip (200 sq ft) getting a 4-inch topsoil layer with 10% settling allowance: 200 × (4 ÷ 12) = 66.7 cu ft; × 1.10 = 73.3 cu ft = 2.71 cu yd. In 2 cu ft bags: 73.3 ÷ 2 = 36.7, rounded up to 37 bags.
Practical cautions
- Measure the actual area — curved beds and slopes hide more square footage than they look.
- Ask the supplier whether bulk topsoil is sold by the cubic yard loose or settled; the difference affects how much arrives.
- Protect delivered soil with a tarp if you cannot spread it the same day; rain turns a pile into heavy mud.
- For existing lawns, core-aerate before topdressing so the new soil works into the root zone.
The Topsoil Calculator handles rectangular, circular, and custom areas with bag counts and optional cost.