How deep should topsoil be for a new lawn?

Four to six inches of good topsoil over prepared sub-grade. Less than four inches dries out fast and the grass struggles in the first hot spell. Loosen the sub-grade before spreading so roots can pass through the interface.

How much does a yard of topsoil weigh?

Roughly 2,000–2,200 lb dry, and up to 2,700 lb wet. That is around a ton per cubic yard, which is worth knowing before you plan to move it by wheelbarrow.

How many bags of topsoil in a cubic yard?

About 36 bags at the common 0.75 cubic foot size. Past roughly ten bags, bulk delivery by the yard is usually cheaper even after the delivery fee.

What is the difference between topsoil and garden soil?

Topsoil is screened native soil — a base material. Garden soil and raised-bed mixes are blends with compost and amendments added. Filling a raised bed entirely with topsoil gives you a dense bed that drains poorly.

How much topsoil for a raised bed?

Multiply the bed dimensions by depth. A 4 × 8 ft bed 12 inches deep needs 32 cubic feet, about 1.2 cubic yards. Most gardeners use a mix of roughly 60% topsoil to 40% compost rather than topsoil alone.

Should I till topsoil into existing soil?

Loosen the existing surface before spreading rather than tilling deeply. A sharp boundary between new topsoil and compacted sub-grade acts as a barrier to roots and water, which is the usual reason a new lawn fails on top of good soil.

How do I top-dress a lawn with topsoil?

Spread a quarter to half an inch and rake it into the grass, so the blades still show through. A 1,000 ft² lawn at half an inch needs about 1.5 cubic yards. Anything thicker smothers the grass you are trying to improve.

How much topsoil do I need?

Multiply the area by the depth in feet and divide by 27 for cubic yards, which is how topsoil is sold in bulk. The depth depends entirely on what you are doing: four to six inches for a new lawn, twelve or more for a raised vegetable bed, and only a quarter to half an inch when top-dressing existing grass — spread thicker than that and you smother the lawn you are trying to improve. Weight matters here more than with most materials, because topsoil is heavy and people routinely underestimate the labour. A cubic yard is roughly a ton dry and closer to 1.35 tons wet, so a modest three-yard order is three tons to move by wheelbarrow. Loosen the existing surface before spreading rather than laying new soil onto compacted ground. A sharp boundary between fresh topsoil and hard sub-grade acts as a barrier to roots and water, and it is the usual reason a new lawn struggles despite good soil on top.

Worked example

A 20 × 10 ft lawn area at 6 inches deep

1Convert depth: 6 in ÷ 12 = 0.5 ft
2Volume: 20 × 10 × 0.5 = 100 ft³
3Cubic yards: 100 ÷ 27 = 3.7 yd³
4Weight at ~2,100 lb/yd³ dry: 3.7 × 2,100 = 7,770 lb

Order 4 cubic yards — just under 4 tons to spread.

Run your own numbers below — the Topsoil Calculator handles the unit conversions and waste factor for you.

Topsoil Calculator

Calculate cubic yards, weight, and bag counts of topsoil for lawns, raised beds, and grading — with density adjusted for moisture.

Formula and figures last reviewed August 6, 2026 — Cosyslabs · how we verify

Inputs

Length(ft)

Width(ft)

Depth(in)

Soil condition

Price per yd³ (optional)($)

Result

Topsoil needed

3.70 yd³

Cubic feet

100 ft³

Weight: 4.00 tons (8000 lb)
0.75 ft³ bags: 134
Density used: 80 lb/ft³ (dry)
Depth: 6.0 in

Diagram

Estimates only. Verify with a licensed contractor or supplier before purchasing. Rough Estimator! is not responsible for shortages, overages, or material variances. See our methodology for formulas and sources.

Formula

Volume yd³ = L × W × (D in ÷ 12) ÷ 27   ·   Weight = ft³ × density (80 lb/ft³ dry, 100 wet)

References

Measure what the tool asks for
This calculator works from length in ft, width in ft and depth in in. Measure the finished area you are covering, not the material — an estimate is only as good as the dimensions you feed it.
What it does with those numbers
Volume yd³ = L × W × (D in ÷ 12) ÷ 27 · Weight = ft³ × density (80 lb/ft³ dry, 100 wet) Every figure on the page comes out of that one expression, so you can check it by hand.
Choosing a soil condition
Pro tip: wet soil can weigh 25% more for the same volume. If you are ordering by the ton after rain, you pay for the water.
Where the numbers come from
The constants are taken from USDA NRCS Soil Health — Soil bulk density guidance and ASTM D5268 — Standard Specification for Topsoil, linked in full below. If a figure here disagrees with your supplier's spec sheet, use the spec sheet — it describes the product you are buying.
What this will not tell you
This is a material takeoff, not a bid. It does not price labour, permits, delivery, equipment hire or site preparation, and it assumes a straightforward layout. Complex cuts, difficult access and awkward shapes all cost more than the geometry suggests.

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Frequently asked questions

Multiply length by width by depth in feet, then divide by 27 for cubic yards. A 20 × 10 ft area at 6 inches deep needs 100 cubic feet, or about 3.7 cubic yards.

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Cite this page

Cosyslabs. (2026). Topsoil Calculator. Rough Estimator!. https://roughestimator.com/topsoil-calculator

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