The 40lb bags of Concrete in a Slab calculator computes the number of 40 pound bags of concrete and water needed for a rectangle (square) slab.
INSTRUCTIONS: Choose units and enter the following:
40 pound bags of Concrete (nb): The calculator returns the number of 40lb bags needed for the slab and the water required to mix it in gallons. However, this can be automatically converted to compatible units via the pull-down menu.
The volume of an 40lb bag of concrete is approximately 0.45 ft3. This calculator computes the volume of the slab in cubic feet and then divides by the cubic feet in an 40lb bag
`nb = (L*W*D) / (0.3 ft^3)`
where: