Container Garden Soil Calculator

About this calculator

For a round pot, soil volume follows the cylinder formula V = πr²h; for a rectangular planter it's simply V = length × width × height. This calculator applies whichever formula matches your container shape, then converts the result from cubic inches or cubic feet into liters or the standard 1.5 cubic-foot potting-soil bags sold at garden centers, so you know exactly how many bags to buy.

Home gardeners, balcony and patio growers, and landscaping professionals use it before filling new planters to avoid buying too little soil (leaving roots cramped) or too much (wasted bags and cost) — especially useful when sizing raised containers, grow bags, or a row of matching pots for a container garden.