Topsoil calculator: cubic yards, bags and weight

How deep should topsoil be?

It depends what is growing in it, and this is where most people either overspend or starve the planting.

Use	Depth
Overseeding an existing lawn	¼ to ½ in
New lawn from seed or turf	4 to 6 in
Flower beds	6 to 12 in
Vegetable beds	12 to 18 in
Raised beds	Full depth of the bed

Convention Horticultural practice rather than a standard. Deeper is not automatically better: most lawn grasses root in the top 6 inches.

How much does topsoil weigh?

Between roughly 1,800 and 2,700 pounds a cubic yard, and moisture is the reason for the spread rather than composition.

The USDA Natural Resources Conservation Service gives an ideal medium-textured soil a bulk density around 1.33 grams per cubic centimetre, which works out near 2,240 pounds a cubic yard dry. Water weighs 62.4 pounds a cubic foot, so soil that has taken on water gets heavy quickly. Wet topsoil can weigh 20 to 50% more than the same volume dry.

This matters if you are ordering by weight. A ton of wet soil is less material than a ton of dry soil, so where you can, order by volume.

Spec USDA NRCS Soil Quality Indicators: Bulk Density gives 1.33 g/cm³ for an ideal medium-textured soil, and 1.0 to 1.4 g/cm³ for undisturbed soils generally. Checked August 2026.

Why add a settling allowance?

Because soil delivered loose contains air, and it will not stay that way. Between the weight of rain, watering and its own mass, freshly spread topsoil settles noticeably in the first few weeks.

Around 10% is the usual allowance, which is trade practice rather than a measured standard. Skipping it is why a bed that looked right on day one sits below the edging by the end of the month.

Common questions

How many bags make a cubic yard?

Bagged topsoil is usually sold in 40 pound bags holding around 0.75 cubic feet, so about 36 bags to the cubic yard. Bulk delivery is far cheaper beyond about a yard, and most suppliers have a minimum delivery of one or two yards.

What is the difference between topsoil, garden soil and compost?

Topsoil is mineral soil, mostly sand, silt and clay, and it is the structural base. Garden soil is topsoil with organic matter blended in. Compost is decomposed organic matter and is an amendment rather than a soil: filling a bed with pure compost gives you something that holds too much water and slumps as it breaks down.

Should I remove the existing grass first?

If you are adding more than about two inches, yes. Grass buried under a thick layer decomposes anaerobically and can create a slippery layer that stops roots and water passing through. Thin top dressing over existing turf is fine and is how lawns are usually levelled.

Is screened topsoil worth paying more for?

For beds and lawns, usually yes: screening removes stones, roots and lumps, and unscreened soil is unpleasant to rake level. For bulk filling behind a wall or under a patio it makes little difference.