How it works
Convert every measurement to feet, multiply length × width × depth to get cubic feet, then divide by 27 (a cubic yard is 3 × 3 × 3 feet). For a circle, the area is π × radius². Weights are typical figures; wet material and different rock types weigh more or less, so check with your supplier.
Cubic yards = length (ft) × width (ft) × depth (ft) ÷ 27
Worked example
A 12 × 10 ft patio slab 4 inches thick: 12 × 10 × 0.333 = 40 cubic feet = 1.48 cubic yards. Concrete is usually ordered with about 10% extra, so 1.6 to 1.75 yards.
Frequently asked questions
How do I calculate cubic yards?
Multiply length, width and depth in feet, then divide by 27. 10 × 10 ft at 3 inches (0.25 ft) = 25 cubic feet = 0.93 cubic yards.
How many cubic feet are in a cubic yard?
27, because a yard is 3 feet and 3 × 3 × 3 = 27.
How much does a cubic yard of gravel weigh?
Roughly 1.4 tons (2,800 lb), depending on the stone and how wet it is. Topsoil is about 1.1 tons, and concrete about 2 tons.
How many square feet does a yard of dirt cover?
About 81 sq ft at 4 inches deep, 108 at 3 inches, and 162 at 2 inches.