Concrete & Area Calculator

How the math works

• Square feet = length (ft) × width (ft).
• Square yards = square feet ÷ 9 (a square yard is 3 ft × 3 ft).
• Cubic feet = square feet × thickness (in) ÷ 12.
• Cubic yards = cubic feet ÷ 27 (a cubic yard is 3 × 3 × 3 ft). Ready-mix concrete is ordered in cubic yards.
• Measured in inches? Square feet = length (in) × width (in) ÷ 144.
• Example: 20 ft × 18 ft at 6 in thick = 360 sq ft = 40 sq yd = 180 cu ft = 6.67 cu yd (7.33 cu yd with 10% extra).

Common thicknesses: 4 in for sidewalks, walkways and patios; 4–6 in for driveways depending on vehicles; aprons are often thicker. Your local requirements may differ.