Converts square feet (ft²) to cubic yards (yd³) by multiplying area by material thickness.
How It Works
Converting ft² to yd³ requires knowing the area and the layer thickness. The formula depends on the unit used for thickness:
Thickness in inches: V (yd³) = A (ft²) × h (in) ÷ 324
Thickness in feet: V (yd³) = A (ft²) × h (ft) ÷ 27
Thickness in yards: V (yd³) = A (ft²) × h (yd) ÷ 9
The calculator handles unit conversion automatically. Enter area in square feet, select the thickness unit, use the quick preset buttons for common depths, and read the volume in cubic yards instantly. The history panel lets you save results and export them as CSV, JPG, or PDF.
Examples
Concrete driveway: A 450 ft² driveway with a 4 in thick slab: 450 × 4 ÷ 324 = 5.56 yd³ of concrete.
Mulch bed: A 200 ft² garden bed with 3 in of mulch: 200 × 3 ÷ 324 = 1.85 yd³ of mulch.
Gravel layer: A 1,200 ft² parking area with 6 in of gravel: 1,200 × 6 ÷ 324 = 22.2 yd³ of gravel.
Topsoil: A 500 ft² lawn area with 1 ft of topsoil: 500 × 1 ÷ 27 = 18.5 yd³ of soil.
FAQ
Why divide by 324 when thickness is in inches?
1 cubic yard = 27 cubic feet = 27 × 12 = 324 square-foot-inches. So ft² × in ÷ 324 gives cubic yards directly.
Can I convert ft² to yd³ without a thickness value?
No. Square feet measure area (2D) and cubic yards measure volume (3D). A thickness or depth is always required to bridge the two dimensions.
How many cubic yards for a 10 × 10 ft slab at 4 inches thick?
100 ft² × 4 in ÷ 324 = 1.23 yd³. Most concrete suppliers recommend ordering 5–10% extra for waste.
How accurate is this calculator?
The formulas are mathematically exact. In practice, add 5–10% to your order to account for spillage, uneven subgrade, and waste.
See also: yd³ to ft² Converter · ft² to ft³ Converter · yd³ to yd² Converter
