MIRR (Modified IRR) Calculator

IRR with explicit reinvestment-rate assumption. Avoids the multiple-IRR problem.

Inputs

Cost of borrowing for the initial investment.

Rate at which interim cash flows are reinvested.

Result

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How to use this calculator

  • Enter initial investment, cash flows, finance rate, and reinvestment rate.
  • Read MIRR.

About this calculator

MIRR addresses two flaws of standard IRR: (1) multiple-IRR for non-conventional flows, (2) the implicit-and-unrealistic assumption that intermediate cash flows are reinvested at IRR itself. MIRR uses two explicit rates: a finance rate for negative flows and a reinvestment rate for positive flows. Always single-valued, more conservative than IRR for typical projects.

Frequently asked

Why is MIRR usually less than IRR?+
Because IRR effectively reinvests at IRR (often unrealistic). MIRR uses a more realistic (typically lower) reinvestment rate.
Finance vs reinvestment rate?+
Finance rate = cost of capital for funding the project. Reinvestment rate = expected rate on intermediate cash flows. Often different.
When does MIRR matter most?+
For non-conventional flows (sign changes), or projects with large early outflows that get reinvested over the life.
Excel's MIRR function?+
Same formula. Often used as a sanity check on IRR for non-conventional flow patterns.
Should I use NPV, IRR, or MIRR?+
NPV first for accept/reject. IRR for intuitive comparison. MIRR when IRR is unreliable due to flow pattern.

Related calculators

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