Topsoil Calculator: How Much Topsoil for a New Lawn or Raised Bed

About

Type the length, width and depth in feet and inches or metres, pick the material, topsoil, garden mix, compost or fill dirt, and the result shows cubic yards, cubic feet and cubic metres, the weight in tons at that material’s density, bags of 0.75, 1, 1.5 or 2 cubic feet, and a 10 percent settling allowance. The arithmetic is area × depth ÷ 27 with typical delivered densities; it is not an AI estimate. For a curved bed or an odd lawn, draw the outline on the canvas below and use that area.

01

The topsoil formula: area, depth, settling

Volume is area times depth: square feet × depth in feet ÷ 27 = cubic yards. A 1,000 sq ft lawn at 3 inches (0.25 ft) is 250 cubic feet, which is 9.3 cubic yards; with the 10 percent settling allowance it is 10.2, so you order 10 or 11. Screened topsoil weighs about 1.2 tons per cubic yard when moderately moist, garden mix about 1.0, compost about 0.9 and fill dirt about 1.3; wet soil can weigh 20 percent more, so if the yard quotes by the ton, ask for their own figure.

Depth is the decision. A new lawn from seed or sod wants 2 to 4 inches of topsoil over the subgrade; topdressing an existing lawn is 1/4 to 1/2 inch, raked in; a raised bed is filled to the depth of the box, usually 10 to 12 inches, and that is better done with a garden mix than straight topsoil. Grading to fix a low spot is whatever the string line says, averaged across the area.

• New lawn: 2–4 in of topsoil, then seed or sod.
• Topdressing: 1/4–1/2 in, worked in with a rake.
• Raised bed: full depth of the box, 10–12 in, garden mix.
• Grading: average depth across the low area, fill dirt below, topsoil on top.

02

How much topsoil for a new lawn

Measure the lawn in sections that are close to rectangles and add them, or draw the whole shape on the canvas. At 3 inches, every 100 sq ft is 0.93 cubic yards, so a 5,000 sq ft front yard is 46 cubic yards, which is four or five dump-truck loads and a job for a skid steer rather than a wheelbarrow. At 2 inches it is 31 yards. Seed wants the top inch fine and level; sod wants the finished grade an inch below walks and edging so the roll sits flush.

03

Raised beds and bags

A 4 × 8 ft bed 12 inches deep holds 32 cubic feet, 1.19 cubic yards, which is 24 bags of 1.5 cubic feet or 18 bags of 2 cubic feet once the 10 percent settling allowance is added; two or three beds tip the balance toward a bulk delivery. Fill the bottom third with the cheaper topsoil or fill and the top with garden mix or compost. Bags are sold by the cubic foot and bulk by the cubic yard; the calculator shows both so the numbers match whichever price list you are reading. Type your price into the cost field for a total.

04

Irregular lawns, and what this is not

A lawn that curves around a bed or a kidney-shaped island is easier to draw than to measure. Draw it on the canvas with the Ground tool as a lawn or garden surface, bend the edges where they curve, read the area, and type it into the calculator with the depth. The drawing is schematic, a planning sketch rather than a survey or a grading plan, and nothing here is an AI estimate. For the plants that go in the bed, the EPA WaterSense guide points to regional lists.