Topsoil Calculator
Enter your bed size to get the topsoil you need in cubic yards and bags, plus an estimated cost. Waste is included.
Topsoil needed
Estimated cost
How to calculate topsoil
Topsoil is sold by volume. For a rectangular bed, multiply length by width by depth, with everything in feet, then convert to cubic yards by dividing by 27.
Formula: cubic yards = length (ft) × width (ft) × depth (in ÷ 12) × (1 + waste %) ÷ 27
Worked example: 20 ft × 10 ft × 6 in bed
Volume = 20 × 10 × (6 ÷ 12) = 100 ft³. Add 10% waste: 110 ft³. Divide by 27: 4.07 cubic yards. In bags, that is 147 bags of 40 lb topsoil.
How deep?
New lawns need 4 to 6 inches of topsoil. Garden beds do well with 6 to 12 inches. Less than 4 inches dries out fast and starves roots.
Common bed sizes
Cost tips
Prices on this page are editable estimates, not quotes. Get 2 to 3 local quotes before you buy, and ask if delivery is included. Delivery, tax and waste can change the total a lot. Order a little extra for cuts and breakage, and confirm final quantities with your supplier or a qualified professional.
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Frequently asked questions
How much topsoil do I need for a 20x10 bed?
A 20 ft by 10 ft bed at 6 inches deep needs about 4.07 cubic yards with 10% waste, which is 147 bags of 40 lb topsoil.
How deep should topsoil be for grass?
4 to 6 inches for a new lawn. Garden beds do well with 6 to 12 inches.
How many bags are in a cubic yard of topsoil?
One cubic yard is about 36 bags of 40 lb topsoil, since each bag is roughly 0.75 cu ft.
Bags or bulk topsoil?
Bulk is usually cheaper for large beds. Bags make sense for small beds and top-ups.
Are the prices accurate?
Prices are editable estimates. The defaults are typical US figures, and your local price can be higher or lower. Delivery fees are not included.