Free potting soil calculator. Calculate exactly how much soil you need for containers, planters, raised beds, and pots in quarts, gallons, or cubic feet.
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Whether you're filling a small flower pot, a window box planter, or a large raised garden bed, knowing exactly how much soil you need prevents waste and ensures you buy the right amount. Our calculator supports rectangular, round, and tapered containers with results in quarts, gallons, and cubic feet.
Soil volume depends on your container's shape. For rectangular containers, multiply length × width × depth. For round pots, use πr²h. Tapered pots require the frustum formula. Our calculator handles all shapes and converts between common units including quarts (the standard for bagged soil) and cubic feet.
Volume Formulas
Rectangular: V = L × W × D | Round: V = πr²h | Tapered: V = πh(r₁² + r₁r₂ + r₂²)/3Avoid multiple trips to the store or having excess soil sitting around.
Bulk soil is cheaper per cubic foot than bags. Know your total needs before buying.
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There are approximately 25.7 dry quarts in a cubic foot. A standard 40-quart bag equals about 1 cubic foot.