How to calculate topsoil
Topsoil is ordered by volume. Multiply length, width, and depth in feet for cubic feet, then divide by 27 for cubic yards:
Cubic yards = (Length ft × Width ft × Depth ft) ÷ 27
A 20 ft × 10 ft bed filled 3 inches deep is 50 cubic feet, or about 1.85 cubic yards.
How deep to spread topsoil
- Top-dressing a lawn: ½–1 inch.
- New sod: 2–4 inches.
- Garden / planting beds: 6–12 inches.
Bulk vs. bags
A 40-lb bag holds about 0.75 cubic feet, so a cubic yard is roughly 36 bags. Past a couple of cubic yards, bulk delivery is much cheaper and faster than hauling bags.
Frequently asked questions
How much topsoil do I need?
Multiply the length, width, and depth in feet to get cubic feet, then divide by 27 for cubic yards. Depth is usually given in inches, so divide it by 12 first. A 20 ft × 10 ft bed at 3 inches deep needs about 1.85 cubic yards.
How deep should topsoil be?
For overseeding or top-dressing a lawn, about ½–1 inch is enough. For new sod, 2–4 inches. For garden beds and planting, 6–12 inches of quality topsoil gives roots room to grow. Match the depth to what you are planting.
How many tons is a cubic yard of topsoil?
About 1.1 tons when relatively dry — roughly 2,200 pounds — though moisture and organic content push it higher. Topsoil is usually sold by the cubic yard for bulk delivery, but this calculator also shows tons in case yours is priced by weight.
How many bags of topsoil are in a cubic yard?
Bagged topsoil is commonly sold in 40-pound bags holding about 0.75 cubic feet, so a cubic yard (27 cubic feet) is roughly 36 bags. For anything more than a few cubic yards, bulk delivery is far cheaper than bags.
Disclaimer: Topsoil weight varies with moisture and organic content, so tonnage is an estimate. Confirm coverage and pricing with your supplier.