Garden Soil Calculator
The Garden Soil Calculator estimates how much topsoil, compost, or garden soil blend you need to fill a bed at your desired depth, in both cubic yards and bags.
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How This Tool Works
Enter your garden bed's length, width, and desired soil depth to see the total volume needed in cubic feet, cubic yards, and bags.
Formula & Method
Volume (cubic feet) = area × (depth in inches ÷ 12). Cubic yards = cubic feet ÷ 27. Bags needed = cubic feet ÷ bag size (default 1.5 cu ft).
Example Calculation
A 4×8 ft raised bed filled 12 inches deep needs 32 cubic feet of soil, or about 1.2 cubic yards — roughly 22 bags of 1.5 cu ft soil.
Frequently Asked Questions
How deep should raised bed soil be?+
Most vegetable raised beds do best with 10–12 inches of quality soil, while shallow-rooted flowers can get by with 6–8 inches.
Should I mix in compost?+
Many gardeners blend 60–70% topsoil with 30–40% compost for the best structure and nutrients — enter your bed size once and buy that ratio across products.
How many bags of soil fill a raised bed?+
It depends on bed size and depth — use the calculator above with your exact dimensions rather than a rule of thumb, since raised beds vary widely in size.
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