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IRR Calculator

Find the internal rate of return of any series of cash flows. Paste the amounts, starting with the initial investment, to get the IRR, an annualized rate for monthly or quarterly flows, the modified IRR and an NPV profile that shows where NPV crosses zero.

Currency

Cash flows, starting with period 0

First value is usually the investment (negative). One per line or separated by spaces/semicolons.

Period length

Discount rate for NPV (optional)

% / yr

Annual rates; converted to monthly or quarterly when needed.

Also calculate MIRR

Finance rate (cost of outflows)

% / yr

Reinvestment rate (inflows)

% / yr

Enter your values to see the result.

How to use the IRR Calculator

Enter the cash flows, starting with period 0. The investment is usually a negative number.
Pick the period length so monthly or quarterly IRRs are also shown as an annual rate.
Optionally enter a discount rate to see the NPV at that rate.
Tick MIRR and enter finance and reinvestment rates for the modified IRR.
Press Calculate IRR to see the rate, the NPV profile chart and the tables.

How IRR is found

The internal rate of return is the rate r that makes the net present value zero:

0 = CF₀ + CF₁/(1 + r) + CF₂/(1 + r)² + … + CF_n/(1 + r)ⁿ

There is no closed-form solution, so the calculator starts Newton–Raphson iteration at 10% (r_new = r − NPV(r) ÷ NPV′(r)) and also scans rates from −99% upward, using bisection on every sign change so that multiple IRRs are not missed.

MIRR = (FV of positive cash flows at the reinvestment rate ÷ PV of negative cash flows at the finance rate)^1/n − 1.

Example: NPV profile of −10,000, 3,000, 4,200, 6,800

Discount rate	NPV
0%	$4,000.00
5%	$2,540.76
10%	$1,307.29
15%	$255.61
20%	−$648.15
25%	−$1,430.40

NPV crosses zero at an IRR of 16.34%. With finance and reinvestment rates of 8%, the MIRR is 14.05%, lower than the IRR because inflows are assumed to earn only 8% when reinvested.

IRR vs. NPV

Use IRR to compare a project's return with your hurdle rate, and NPV to measure how much value it adds. When cash flows change sign more than once or projects differ greatly in size, rely on NPV or MIRR.

Frequently asked questions

What is IRR?

The internal rate of return is the discount rate at which the net present value of all cash flows is exactly zero. It is the average yearly (or per-period) return the investment earns on the money tied up in it.

How is IRR calculated?

There is no direct formula, so IRR is found by trial and error: solve 0 = Σ CFt ÷ (1 + r)^t for r. This calculator uses Newton–Raphson iteration and falls back to bisection, scanning rates from −99% upward to catch every solution.

Why can there be more than one IRR?

If the cash flows change sign more than once, for example an investment, then income, then another large outlay, the NPV curve can cross zero several times. In that case each crossing is a valid IRR and NPV or MIRR is a better guide.

What is MIRR?

The modified internal rate of return assumes positive cash flows are reinvested at a reinvestment rate and outflows are financed at a finance rate: MIRR = (FV of inflows ÷ PV of outflows)^(1/n) − 1. It always has a single answer and is often more realistic than IRR.

How do I annualize a monthly IRR?

Use (1 + monthly IRR)^12 − 1. For example, a 1% monthly IRR equals about 12.68% a year, not 12%. Pick Months as the period length and the calculator does this for you.

What is a good IRR?

An IRR is attractive when it is higher than your cost of capital or the return you could get elsewhere at similar risk. Compare it with your hurdle rate rather than a fixed number.

Does this match Excel's IRR and MIRR functions?

Yes. With the same cash flows, =IRR(values) and =MIRR(values, finance_rate, reinvest_rate) give the same results, assuming equal periods and the first value at period 0.

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