How much concrete you need for slab 8ft by 8ft by 4 inches thick?

To calculate the amount of concrete needed for a slab that is 8 feet by 8 feet and 4 inches thick, first convert the thickness to feet: 4 inches is 1/3 of a foot. The volume in cubic feet is then calculated as 8 ft × 8 ft × (1/3 ft) = approximately 21.33 cubic feet. Since concrete is usually ordered in cubic yards, divide by 27 (the number of cubic feet in a cubic yard): 21.33 / 27 ≈ 0.79 cubic yards. Therefore, you need about 0.79 cubic yards of concrete for the slab.