MIRR Calculator

Use this MIRR calculator to find the modified internal rate of return on an investment, using a realistic reinvestment rate for the cash it returns.

Initial investment US$

Annual cash inflow US$

Years years

Finance rate %

Reinvestment rate %

Modified internal rate of return —

Future value of inflows —

Total cash inflows —

We always strive to use the latest data for every variable so our results and reports are as accurate as possible. Even so, errors are possible — you should not rely on this tool or its report alone, and we accept no liability for any decision made based on it.

What it does

The MIRR Calculator finds the modified internal rate of return for a project or investment: a single upfront outlay followed by a series of annual cash inflows. Unlike the standard IRR, it assumes cash flows are reinvested at a realistic rate you choose, giving a more honest measure of the return you can actually expect.

Data sources & parameters

This calculator uses standard financial formulas and runs entirely in your browser. It needs no external rate data — your result is computed only from the values you enter above.

The formula

MIRR = (FV of positive cash flows ÷ PV of negative cash flows)^(1/n) − 1, where n is the number of years

How it works

Each annual inflow is compounded forward to the end of the horizon at the reinvestment rate, producing a single future value. That future value is compared with the initial investment, and the calculator solves for the annual growth rate that links them.

Where it is used

Ranking capital projects with a realistic reinvestment assumption
Correcting an inflated IRR that assumes reinvestment at the IRR itself
Comparing an investment against a financing or hurdle rate

Worked example

A project needs $100,000.00 up front and returns $30,000.00 each year for 5 years, with inflows reinvested at 10%. The inflows grow to …, giving a modified internal rate of return of ….

What the MIRR calculator does

The MIRR calculator works out the modified internal rate of return on an investment or project with a single upfront outlay followed by a steady stream of annual cash inflows. It gives the annual rate of return the investment delivers once you account for how the returned cash is reinvested, which makes it useful for comparing opportunities that pay out over time.

Why MIRR exists

The internal rate of return (IRR) implicitly assumes that every cash inflow a project generates is reinvested at the IRR itself. For a project with a very high IRR, that is unrealistic: you would need somewhere equally lucrative to put each payout, and such opportunities are rare.

The modified internal rate of return lets you set a separate reinvestment rate, one you could achieve on the cash as it arrives. The result is usually lower than the IRR and closer to the return you can expect to compound over the life of the investment.

Analysts often prefer MIRR for ranking competing projects. Two investments can share the same IRR yet differ once realistic reinvestment is included, and MIRR shows that difference.

How the calculation works

Each positive cash inflow is carried forward to the end of the investment horizon, growing at the reinvestment rate for the years that remain. Adding these compounded inflows gives a single future value: the cash you would hold at the end if every payout were reinvested at your chosen rate.

The calculator then solves for the constant annual growth rate that turns the initial outlay into that future value over the full term. That rate is the MIRR.

Formally, MIRR equals the future value of positive cash flows divided by the present value of negative cash flows, raised to the power of one over the number of years, minus one. With a single upfront outflow, the present value of negatives is that outflow, and the finance rate has nothing earlier to discount.

The inputs

The initial investment is the upfront cash you commit. A larger outlay, for the same inflows, lowers the MIRR.
The annual cash inflow is the amount the investment returns each year, treated as a level series across the term.
Years is how long the investment runs. A longer horizon gives early inflows more time to compound.
The finance rate discounts outflows. It is kept for completeness and for projects with staggered outflows.
The reinvestment rate is the rate at which returned cash is assumed to grow, and it is what separates MIRR from a naive return figure.

Reading the results

The calculator reports the MIRR as an annual percentage, the future value of the inflows (everything the investment paid you, compounded), and the total cash inflows (the simple sum of the payouts). The gap between the future value and the total cash flow is the contribution of reinvestment, which can be large when the reinvestment rate is high or the term is long.

Using MIRR well

The result depends on the reinvestment rate you choose. Setting it too high inflates the return and brings back the problem MIRR was designed to solve.

Run several scenarios: a conservative reinvestment rate for a cautious view and a more optimistic one for the upside. Judge the investment against that range and against your hurdle rate, the minimum annual return you require.

If an investment pays back far more than you put in but still shows a modest MIRR, time and scale are at work: a large outlay recovered slowly is not the same as a small one recovered quickly.

Common mistakes

Choosing an unrealistic reinvestment rate. Pick a rate you could earn on the returned cash.
Ignoring the length of the term. A high annual inflow over a short period behaves very differently from the same inflow over many years.
Comparing MIRR with IRR directly. They rest on different assumptions, so a lower MIRR does not mean a project got worse, only that the figure is more conservative.

This article is general information only and is not financial advice.

About This MIRR Calculator

Use this MIRR calculator to get an instant estimate based on the figures you enter. Adjust the inputs above to match your situation, or browse all our calculators to plan your next step.

Frequently asked questions

What does the MIRR calculator work out?

It works out the modified internal rate of return: the annual growth rate that links your initial investment to the future value of all cash inflows, assuming those inflows are reinvested at a rate you choose. It returns the MIRR percentage, the future value of the inflows, and the total cash received.

How is MIRR different from IRR?

The standard IRR assumes every cash inflow is reinvested at the IRR itself, which is often unrealistic and can flatter a project. MIRR lets you set a separate, realistic reinvestment rate, so it usually gives a lower and more realistic figure for the return you can expect.

What reinvestment rate should I use?

Use a rate you could actually earn on the cash as it comes in, such as your portfolio's expected return or a safe deposit rate. A conservative rate gives a cautious MIRR; a higher rate assumes you can consistently redeploy the cash at that level.

What is the finance rate for?

The finance rate discounts cash outflows to present value. With a single upfront investment there is nothing earlier to discount, so it does not change the result here, but it matters when a project has outflows spread across several years.

Can MIRR be lower than the reinvestment rate?

Yes. If the total cash returned is modest relative to the initial outlay, the MIRR can fall below the reinvestment rate even though inflows compound at that rate, because the initial investment was large compared with what came back.

Is my data kept private?

Yes. The calculation runs entirely in your browser. Nothing you enter is uploaded, stored, or shared with anyone.

About the author

Written and reviewed by

Taha Kheirandish

Economics student and independent researcher

Taha Kheirandish reads tax codes the way other people read maps — to find out where a system actually leads, not where it claims to go.

He is an economics student, and his work here is comparative by design. A pension deferral bonus in Quebec, a commuting allowance in Germany, a rent-increase ceiling in the Netherlands: each is a decision a government made about how money should move, and each reads differently once you set it beside eight others. He builds and checks these calculators across nine markets from primary sources — the regulation rather than a summary of it, the ministry’s own circular rather than a news item quoting it.

That is the editorial standard of the site as well as his habit. Every rate, threshold and bracket here carries the document it was read from and the date it takes effect, and gets re-checked when the law moves rather than when someone happens to notice.

He is a researcher, not a licensed adviser, and nothing on this site is personal financial advice. It is arithmetic done carefully with its sources shown — so that you can check it, and take it to someone who is.

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