Financial Calculators
MIRR Calculator
Calculate the Modified Internal Rate of Return (MIRR) from an initial investment, cash flows, finance rate, and reinvestment rate locally in your browser.
This private browser estimate finds the Modified Internal Rate of Return (MIRR), which assumes positive cash flows are reinvested at the reinvestment rate and negative cash flows are financed at the finance rate. 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, or irregular timing.
Find the modified internal rate of return with separate finance and reinvestment rates.
Enter the initial investment paid out at time 0, the expected cash flows per period, the finance rate for discounting outflows, and the reinvestment rate for compounding inflows. The calculator computes MIRR = (FV of positive cash flows at reinvestment rate / |PV of negative cash flows at finance rate|)^(1/n) - 1. For example, a $10,000 investment returning $3,000, $4,000, $5,000, and $6,000 with a 10% finance rate and 10% reinvestment rate gives a MIRR of about 21.86%. This private browser estimate assumes end-of-period cash flows and constant rates, and 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 Modified Internal Rate of Return (MIRR)?
MIRR is a variation of IRR that uses a separate finance rate for discounting negative cash flows and a reinvestment rate for compounding positive cash flows. It solves the unrealistic IRR assumption that all cash flows are reinvested at the IRR itself. The formula is MIRR = (FV of positive cash flows at reinvestment rate / |PV of negative cash flows at finance rate|)^(1/n) - 1, where n is the number of periods.
How does MIRR differ from IRR?
IRR assumes all interim cash flows are reinvested at the IRR, which can overstate returns when the IRR is high. MIRR lets you specify a realistic reinvestment rate (often your cost of capital or a safe rate) and a finance rate for any additional outflows. MIRR also produces a single rate even when cash flows change sign multiple times, avoiding the multiple-IRR problem.
What finance rate and reinvestment rate should I use?
The finance rate is the cost of borrowing or the rate at which you would fund additional outflows — often your weighted average cost of capital. The reinvestment rate is what you could earn on positive cash flows — often a risk-free rate or your portfolio return. Using the same rate for both gives a result closer to the geometric mean return.
When should I use MIRR instead of IRR?
Use MIRR when you want a more realistic measure that reflects your actual financing and reinvestment opportunities, when comparing projects of different sizes or timing, or when the cash flow series has multiple sign changes that make IRR ambiguous. For a single sign-change series with equal finance and reinvestment rates, MIRR will equal the IRR only in special cases.
What inputs are accepted?
Enter an initial investment greater than zero (up to 1,000,000,000,000), up to 1,000 cash flows (one per line or comma-separated), a finance rate percentage (greater than -100%, up to 100%), and a reinvestment rate percentage (greater than -100%, up to 100%). At least one cash flow must be positive for MIRR to exist. Negative cash flows represent additional outflows. Missing, non-numeric, or out-of-range entries show a clear message. The calculation runs locally in your browser; CodeASystem does not upload or store your values, and this is not financial, investment, or tax advice.