Calculate MIRR with separate finance and reinvestment rates. Compare against standard IRR, see NPV, cash flow schedule, and reinvestment rate sensitivity.
The Modified Internal Rate of Return (MIRR) solves the two biggest problems with standard IRR: the unrealistic reinvestment rate assumption and the possibility of multiple IRRs when cash flows change sign more than once.
Standard IRR assumes all positive cash flows are reinvested at the IRR itself — a rate that's often unrealistically high. MIRR uses two realistic rates instead: a finance rate for discounting negative cash flows (your cost of capital) and a reinvestment rate for compounding positive cash flows (your actual reinvestment opportunity).
The formula computes: (1) PV of all negative cash flows discounted at the finance rate, (2) FV of all positive cash flows compounded at the reinvestment rate, then (3) MIRR = (FV/PV)^(1/n) − 1. This always produces a single, unique answer. MIRR is typically lower than IRR for high-return projects, revealing how much of IRR's optimism came from the reinvestment assumption.
Use the preset examples to load common values instantly, or type in custom inputs to see results in real time. The output updates as you type, making it practical to compare different scenarios without resetting the page.
Standard IRR frequently overstates returns by assuming reinvestment at the IRR. MIRR provides a more conservative and realistic measure of project value, helps compare projects of different sizes and durations, and always yields a unique solution.
This tool is designed for quick, accurate results without manual computation. Whether you are a student working through coursework, a professional verifying a result, or an educator preparing examples, accurate answers are always just a few keystrokes away.
PV_neg = |Σ(negative CFs / (1 + finance_rate)^t)| FV_pos = Σ(positive CFs × (1 + reinvest_rate)^(n−t)) MIRR = (FV_pos / PV_neg)^(1/n) − 1
Result: MIRR = 8.92% vs IRR = 12.8%
The standard IRR of 12.8% assumes reinvestment at 12.8%. MIRR at 8.92% uses realistic rates: 6% finance and 4% reinvestment. The 3.9pp gap shows how much IRR overstated the true return.
Use consistent units throughout your calculation and verify all assumptions before treating the output as final. For professional or academic work, document your input values and any conversion standards used so results can be reproduced. Apply this calculator as part of a broader workflow, especially when the result feeds into a larger model or report.
Most mistakes come from mixed units, rounding too early, or misread labels. Recheck each final value before use. Pay close attention to sign conventions — positive and negative inputs often produce very different results. When working with multiple related calculations, keep intermediate values available so you can trace discrepancies back to their source.
Enter the most precise values available. Use the worked example or presets to confirm the calculator behaves as expected before entering your real data. If a result seems unexpected, compare it against a manual estimate or a known reference case to catch input errors early.
Because IRR assumes reinvestment at the (high) IRR, while MIRR uses a more conservative reinvestment rate. The gap widens as IRR gets higher.
When the reinvestment rate and finance rate both equal the IRR. This is the special (unrealistic) case that standard IRR assumes.
Your cost of capital: WACC for corporate projects, mortgage rate for real estate, or the rate you'd pay to fund the investment. Understanding this concept helps you apply the calculator correctly and interpret the results with confidence.
The return you can realistically earn on the received cash: savings account (1-2%), bond fund (3-5%), or blended portfolio return (5-8%). Use this as a practical reminder before finalizing the result.
Yes. When cash flows change sign more than once, IRR may have multiple solutions. MIRR always produces a single, unique answer.
NPV is theoretically cleaner for ranking projects. MIRR is useful when stakeholders prefer a percentage return metric that doesn't have IRR's flaws.