Convert an area in square feet (ft²) to cubic feet (ft³) by entering the area and the thickness or depth. 100 ft² at 4 in thick equals 33.3333 ft³.
333.3333 ft3
100 ft² × 4 in ÷ 12 = 33.3333 ft³
| Area (ft²) | Thickness | Volume (ft³) | Volume (yd³) |
|---|
How to convert square feet to cubic feet
Volume in ft³ = area in ft² × thickness. If the thickness is in inches, divide by 12 first: ft³ = ft² × in ÷ 12. If the thickness is already in feet: ft³ = ft² × ft.
Common example
A 100 ft² concrete slab at a 4 in thickness needs 33.33 ft³ of concrete (about 1.24 yd³, since 1 yd³ = 27 ft³).
Common mistake
Square feet is area; cubic feet is volume. You cannot convert between them without a thickness. Entering the thickness in the wrong unit (inches into the feet formula, or vice versa) changes the result by a factor of 12.
Cubic feet to square feet (ft³ to ft²) · Square feet to cubic meters · Cubic feet calculator
