The weighted average cost of capital (WACC) is calculated using the formula WACC = (E/V) * Re + (D/V) * Rd * (1-T), where E is the market value of the company's equity, V is the market value of the company's total capital, Re is the cost of equity, D is the market value of the company's debt, Rd is the cost of debt, and T is the corporate tax rate.