How Much Topsoil for a 20×20 garden?
This calculator is pre-filled to estimate the topsoil for a 20×20 garden. Change any field to match your project, and enter your local price for a precise cost.
Quick answer: A 20×20 garden at a 3 in depth needs about 3.70 cubic yards of topsoil (100 cu ft) — roughly 134 40 lb bags.
Topsoil calculator
How it's calculated: Length ft × width ft × (depth in ÷ 12) = cubic feet; divide by 27 for cubic yards, or by 0.75 for the number of 40 lb bags.
How to estimate topsoil
- For a new lawn, 4-6 inches of quality topsoil gives roots room to establish.
- Raised beds usually want the full bed depth; mix topsoil with compost for better structure.
- Bulk topsoil is far cheaper than bags for anything larger than a small bed.
- Look at bulk topsoil before it is dumped - screened soil should be crumbly, dark and free of rocks, roots and clay clods.
- Loosen compacted subsoil before spreading topsoil over it; roots and water stop dead at a hard layer.
Frequently asked questions
How Much Topsoil for a 20×20 garden?
A 20×20 garden at a 3 in depth needs about 3.70 cubic yards of topsoil (100 cu ft) — roughly 134 40 lb bags.
How many 40 lb bags of topsoil in a cubic yard?
About 36 bags of 0.75 cubic feet each, so bulk is cheaper for larger jobs.
How much does a cubic yard of topsoil weigh?
Roughly 1 to 1.3 tons depending on moisture. A heaped load of wet soil can exceed a pickup's payload, so plan delivery for anything over a yard or two.
What is the difference between topsoil and garden soil?
Topsoil is the screened mineral base; garden soil and compost blends are amendments with organic matter mixed in. For raised beds, topsoil blended with compost beats either one alone.
How much topsoil for topdressing a lawn?
A thin 1/4 to 1/2 inch layer is all an existing lawn can take - that is one cubic yard per roughly 650-1,300 sq ft. Any deeper smothers the grass.
Screened or unscreened topsoil?
Screened costs more but saves hours of raking out rocks and roots - worth it for lawns and planting beds. Unscreened is fine for rough fill and grade changes that get covered anyway.