IRR - Internal Rate of Return, a financial measure of the profitability of the investment
IRR is a financial metric that brings future cash flows into the present, commonly used to measure the profitability of long-term investments with distant future returns, such as agroforestry systems.
The textbook definition of IRR is “the discount rate at which your investment’s Net Present Value (NPV) equals 0.”
$NPV = \frac{Cash Flow₁}{(1 + r)₁} + \frac{Cash Flow₂}{(1 + r)₂)} + ... + \frac{Cash Flowₙ}{(1 + r)ₙ} - Initial Investment$
where r = the discount rate and n = the number of periods
In interpreting your IRR, a project with a high IRR (e.g. 10%) can be seen as a better investment, indicating your rate of return exceeds the cost of capital. By contrast, low or negative IRR (e.g. -1%) indicate low profitability and a poor investment, suggesting your rate of return is small relative to or less than your initial investment. An IRR of 0 suggests no returns.
Practically, IRR is used as a benchmark against a project’s discount rate and interest rate to determine the viability of an investment. It allows investors to compare projects of different sizes to determine the better investment opportunity.