Formula
Volume = π × (diameter ÷ 2)² × height, in cubic inches, ÷ 1,728 = cubic feet. Example: 12 in × 12 in = about 0.79 cubic feet. Tapered pots hold less — treat this as an upper estimate and buy a little less if your pot narrows sharply.
Calculate potting mix volume for a round pot from diameter and height. Tapered pots hold less than a straight cylinder.
Volume = π × (diameter ÷ 2)² × height, in cubic inches, ÷ 1,728 = cubic feet. Example: 12 in × 12 in = about 0.79 cubic feet. Tapered pots hold less — treat this as an upper estimate and buy a little less if your pot narrows sharply.