IRR (Internal Rate of Return) is a financial metric used to determine the profitability of a potential investment. Also, IRR is a discount rate in which the net present value (NPV) of the cash flows is equal to zero. It is majorly used for discounted cash flow analysis. Furthermore, it helps in comparing the potential annual rate of return over time.  ROI (Return on Investment) measures the total growth or return from an investment. In simple words, ROI is a percentage increase or decrease of investment from the start till the end. Moreover, ROI is not a measure of the annual rate of return. On the other hand, IRR measures the annual growth rate from an investment. This is one of the differences between them. Another difference is that both ROI and IRR numbers will be the same for a year; however, they will differ for a longer duration.