Compost Calculator
Enter your size to get compost quantity, plus an estimated cost. Waste is included and prices are editable.
Material needed
Estimated cost
This result tells you how many cubic yards of compost to buy for the area and depth entered, including waste, and the estimated material cost, so the bed is filled to the planned depth without ordering far more than needed.
How to calculate compost
Compost. Enter length, width and depth to get cubic yards.
Formula: volume = length × width × (thickness ÷ 12) ÷ 27 = 1.23 cubic yards. With 10% waste: 1.36 cubic yards.
Worked example
Example: 10 ft × 10 ft at 4 inches thick = 1.23 cubic yards. With 10% waste: 1.36 cubic yards, about $48 at $35 per cubic yard.
Tips
Measure the full area, then subtract large openings if you want an exact count. Order a little extra for cuts and breakage, and confirm quantities with your supplier before you buy.
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Frequently asked questions
How much compost do I need?
Example: 10 ft × 10 ft at 4 inches thick = 1.23 cubic yards. With 10% waste: 1.36 cubic yards, about $48 at $35 per cubic yard.
How much waste should I add?
Add 10% for straight areas and 15% for areas with many cuts, corners and openings.
Are the prices accurate?
Prices are editable estimates. The defaults are typical US figures, and your local price can be higher or lower.