About this tool
Compute concrete volume for a rectangular slab in cubic yards (the standard ordering unit in the US) and cubic meters (rest of world). Includes a 10 % waste buffer.
Formula
cubicFeet = length × width × (depth / 12). cubicYards = cubicFeet / 27.
Worked example
20 × 10 × 4 in → 800 ft³ × ⅔ = 533 ft³? No: 20·10·(4/12) = 66.7 ft³ = 2.47 yd³. Order ≈ 2.7 yd³.
Notes
For large pours, get a structural engineer involved. Concrete trucks typically deliver 8–10 yd³ per load with a partial-load fee for less.