How to Calculate Cubic Yards

Cubic yards are the standard unit for bulk materials like dirt, gravel, mulch, and concrete. The formula is: cubic yards = (length ft × width ft × depth ft) ÷ 27.

Depth is usually the tricky part, since most projects specify depth in inches, not feet. Convert first: divide inches by 12. So a 4-inch depth becomes 0.333 ft before you multiply.

Example: a 10 ft × 10 ft area at 4 inches deep is 100 sq ft × 0.333 ft = 33.3 cubic feet, which is 33.3 ÷ 27 ≈ 1.23 cubic yards. Add a waste allowance — 10% is a common default — for compaction, spillage, and uneven ground.