Example 1 Length Around a Circle, 18' Round Swimming Pool 18' x 3.1416 = 56.55' (total linear feet around pool) To add 2' of stone around this pool 3' deep: 56.55' x 2' = 113.10' 113.10' x .25 (3" depth) = 28.28 Cubic Feet 28.28 / 27 = 1.05 Cubic Yards
Example 2 Square Footage Inside a Circle, 24' Round Swimming Pool 24' x 24' = 576' 576' x .7854 = 452.39 Square Feet (total inside pool) To add 4" of sand evenly across pool: 452.39' x .33 (4" depth) = 149.29 Cubic Feet 149.29 / 27 = 5.53 Cubic Yards To be safe, always round up. You would order 6 Cubic Yards of sand.
Square Footage Inside of a Circle: Length x Width x .7854 = Square Feet	Length Around a Circle: Diameter x 3.1416 = Linear Feet Around a Circle