How this calculator works
It multiplies your area by the spread depth for the volume, then shows it as cubic yards (bulk) and 1.5 cubic-foot bags.
Worked example — a 20 ft × 10 ft bed at 2 inches:
200 × (2 ÷ 12) = 33.3 cubic feet → ÷ 27 = 1.23 cubic yards, or about 23 bags.
200 × (2 ÷ 12) = 33.3 cubic feet → ÷ 27 = 1.23 cubic yards, or about 23 bags.
How thick to spread compost?
A 1–2 inch top dressing is plenty for established beds; mix 2–3 inches into new beds before planting.
Frequently asked questions
How many bags of compost in a yard?
About 18 bags of the 1.5 cubic foot size make one cubic yard.
How deep should compost be?
1–2 inches as a top dressing, more when amending new soil.