The Internal Rate of Return (IRR) is a core concept in corporate finance and investment analysis. It is the discount rate at which the Net Present Value (NPV) of a series of cash flows becomes exactly zero. In simpler terms, it's the expected annualized rate of growth that an investment is projected to generate. If the IRR of a project is higher than a company's required rate of return or cost of capital, the project is generally considered a good investment. This calculator is designed to find the IRR for a series of periodic and regular cash flows. To use the IRR calculator, you need to input a series of cash flows that are assumed to occur at regular intervals (e.g., annually). Enter these cash flows into the text area, separated by commas or spaces. A critical convention is that the first cash flow must be the initial investment, and it must be entered as a negative number. All subsequent cash flows represent the inflows or returns generated by the investment, and these should be entered as a positive number. For example, an investment of $1000 that returns $200, $300, $400, and $500 over the next four years would be entered as '-1000, 200, 300, 400, 500'. After you've listed your cash flows, click the 'Calculate IRR' button. The tool uses a numerical method (like the Newton-Raphson algorithm) to iteratively find the rate that solves the NPV equation. The resulting IRR is then displayed as a percentage.