Financial Calculators
IRR Calculator
Find the internal rate of return (IRR) for an initial investment and a series of cash flows, with NPV verification and multiple-IRR detection, locally in your browser.
This private browser estimate finds the per-period discount rate that sets an investment's net present value to zero. Enter one cash flow per period, at the end of each period; the initial investment is paid out at time 0. It does not account for fees, taxes, reinvestment, or irregular timing.
Find the discount rate that sets an investment’s net present value to zero.
Enter the initial investment paid out at time 0 and the expected cash flows, one per line or comma-separated. The calculator searches for the per-period rate that makes the net present value of those cash flows equal to zero and reports it as the IRR, the NPV at that rate as a check, the undiscounted total and net gain or loss, and a present-value breakdown for every period. For example, a $10,000 investment returning $3,000, $4,000, $5,000, and $6,000 has an IRR of about 24.89%. When the series changes sign more than once several rates solve it, so the calculator lists every rate it finds and flags the ambiguity. This private browser estimate assumes one investment at time 0, end-of-period cash flows, and a constant reinvestment rate, and it does not account for fees, taxes, inflation, or irregular timing. It is not financial, investment, or tax advice; your values are not uploaded or stored.
Frequently Asked Questions
Everything you need to know about this tool, how it works, and privacy.
What is the internal rate of return (IRR)?
The IRR is the per-period discount rate that makes an investment’s net present value equal to zero: 0 = -I + CF1/(1+r) + ... + CFn/(1+r)^n, where I is the initial investment and CF are the cash flows. It is the break-even growth rate of the money you put in, so a project whose IRR beats your required return (hurdle rate) generally adds value. For example, a $10,000 investment paying back $3,000, $4,000, $5,000, and $6,000 over four periods has an IRR of about 24.89%.
How does the calculator find the IRR?
There is no closed-form formula for the IRR in general, so the calculator evaluates the NPV across a wide range of rates, finds where it crosses zero, and refines that point by repeated bisection until the rate is precise to about 14 decimal places. It then shows the NPV at the solved rate — which rounds to zero — plus the present value of every cash flow at that rate, so you can verify the result rather than take it on faith.
Why can cash flows have more than one IRR?
A conventional investment changes sign once: you pay out first and receive afterwards. When the series changes sign more than once — for example an operating cost late in a project — more than one positive rate can set the NPV to zero, because the number of positive real roots is at most the number of sign changes. When that happens the calculator lists every rate it finds (up to six) and flags the ambiguity; compare each rate with the NPV Calculator, or simply use NPV directly at your hurdle rate.
How is IRR different from NPV?
NPV answers “how much value does this add at a given discount rate?”, while IRR answers “at what rate does it break even?”. For a series with a single sign change, the NPV is positive at rates below the IRR and negative at rates above it. The two can still rank projects differently when scale or timing differs, because IRR implicitly assumes cash is reinvested at the IRR itself, while NPV lets you use a realistic reinvestment rate.
What is a good IRR?
It depends on your opportunity cost: compare the IRR with your required return, cost of capital, or an alternative investment, not with zero. A 15% IRR means little when comparable investments pay 20%. Watch scale too — a huge IRR on a tiny outlay may earn almost nothing in absolute terms — and remember the reinvestment assumption behind the figure. Check the NPV and payback period alongside it for a fuller picture.
What inputs are accepted?
Enter an initial investment greater than zero (up to 1,000,000,000,000) and up to 1,000 cash flows, one per line or comma-separated, in the same currency units. At least one cash flow must be greater than zero for a rate to exist, and negative cash flows are allowed because they represent money paid out. Missing, non-numeric, or out-of-range entries show a clear message instead of a misleading result. The calculation and copy run locally in your browser; CodeASystem does not upload or store your values, and this is not financial, investment, or tax advice.