Difference between Residual Income & Return on Investment Definitions and meanings: Return on investment: Return on investment (ROI) is a measure which calculates the efficiency of an investment by calculating percentage of return earned by that investment. Residual income: Residual income (RI) is the amount of income an investment opportunity generates above the minimum level of rate of return. Formulas and example: The formulas for the calculation of return on investment (ROI) and Residual income (RI) are given below: Return on investment = (Profits or return/Total Long-term investment) × 100 Residual income = Net operating Income – (Average operating assets × Minimum rate of return)