The basic WACC equation The calculation of WACC involves calculating the weighted average of the required rates of return on debt and equity, where the weights equal the percentage of each type of financing in the firm's overall capital structure. r_s r_e r_p r_d is the symbol that represents the before-tax cost of debt in the weighted average cost of capital (WACC) on. Mitchell Co. has $1.4 million of debt, $2.5 million of preferred stock, and $2.2 million of common equity. What would be its weight on debt? 0.23 0.36 0.45 0.41