A cubic yard is the volume of a cube that measures 3 feet on every side: 3 × 3 × 3 = 27 cubic feet, or about 0.765 cubic meters. When a contractor says “a yard of concrete” or “two yards of mulch,” this is the unit they mean. Ready-mix plants, quarries and landscape suppliers across the US price bulk material per cubic yard.
To get cubic yards from a flat area, multiply length (ft) × width (ft) × depth (in) ÷ 12 for cubic feet, then ÷ 27. A shortcut: yd³ = square feet × depth in inches ÷ 324. A 10’ × 10’ slab 4” thick is 100 × 4 ÷ 324 = 1.23 yd³. Flip it around and one yard covers 324 sq ft at 1”, 162 sq ft at 2”, 108 at 3”, 81 at 4” and 54 at 6”.
Bagged products are labeled in cubic feet instead, so convert before comparing: one yard equals 45 × 80 lb concrete bags (0.60 cu ft each) or 13.5 × 2 cu ft mulch bags. Ready-mix is ordered in ¼-yard increments, and most plants add a short-load fee below 3–4 yards.