How much topsoil for a 4 x 8 area?
Short answer
- A 4 x 8 ft area is 32 square feet. At 4 inches deep it needs 0.4 cubic yards (10.7 cubic feet) of topsoil.
- With 10% extra: 0.5 tons or 12 bags of 1 cu ft (0.43 cubic yards).
- It's typically a raised garden bed.
Topsoil for a 4 x 8 area at 2, 4, 6 inches
Cubic yards are shown without extra so you can compare quotes. The other columns include 10% extra, and tons use 80 lb per cubic foot. Ask your supplier for the exact weight of their material.
Open this area in the topsoil calculator to change the size, depth, extra or material.
How the math works
4 ft × 8 ft = 32 sq ft. At 4 inches deep that's 32 × 4 ÷ 12 = 10.7 cubic feet, and ÷ 27 = 0.4 cubic yards. Adding 10% gives 11.7 cubic feet to buy.
How deep should it be?
Penn State Extension recommends at least 4 to 6 inches of good topsoil for a new lawn, measured after it settles. To improve an existing garden bed, Miracle-Gro's directions are to spread 2 to 3 inches and mix it into the top 6 to 8 inches. Loose soil settles once it's watered and walked on, which is why we add 10% extra.