1. A method for converting a first type of concrete reinforcing material to an equivalent quantity of concrete reinforcing fiber for designing a reinforced concrete slab, the reinforced concrete slab using the concrete reinforcing fiber instead of the first type of concrete reinforcing material, comprising: a) determining whether a slab to be reinforced is a lightly reinforced slab on which loads to be carried are not excessive; b) using the spacing theory to get a minimum fiber dosage for a given concrete slab thickness, if the slab to be reinforced is a lightly reinforced slab; c) using an equivalent area of steel calculation to determine a proper fiber dosage, if the minimum fiber dosage for a given concrete slab thickness is insufficient to give a residual strength factor greater than 30 percent; d) using an equivalent moment capacity calculation to determine a proper fiber dosage, if the minimum fiber dosage for a given concrete slab thickness is sufficient to give a residual strength factor greater than 30 percent; and e) providing a tabulation in the form of a fiber reinforced concrete design calculator, the fiber reinforced concrete design calculator including: 1) a first input field including a first set of data corresponding to a first type of concrete reinforcing material; and 2) a first output field including a first set of data corresponding to a first type of concrete reinforcing fibers to be used instead of the first type of concrete reinforcing material for designing a reinforced concrete slab.