How Much Compost for a 20x20 Area?
For a 20x20 area of compost at 2 inches deep, you need about 2.47 cubic yards - roughly 67 bags (1 cu ft bag). The amount changes with depth; the table below shows common depths, and you can adjust everything in the calculator.
Based on a 20x20 area (400 sq ft). One cubic yard = 27 cubic feet; bags are 1 cu ft bag.
0.25-0.5 in to top-dress a lawn, 1-3 in to amend a bed before digging in.
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For a new or tired planting bed, spread 1 to 3 inches of compost and dig or till it into the top several inches of soil. For an established lawn, a thin quarter to half inch top-dressing is enough.
Measure the bed in feet, set the depth, and the calculator returns cubic yards and the number of bags for the size you buy.
Other compost amounts
Same area, other materials
Need a different size? Open the full Compost calculator →