Modified IRR (MIRR) Calculator

Accurately evaluate investment profitability by defining distinct financing and reinvestment rates.

Cash Flow Analysis

Period	Cash Flow	PV of Outflows	FV of Inflows

This table details the calculation of present and future values for each period’s cash flow.

What is a Modified IRR Calculator?

A modified IRR calculator is a financial tool used to determine the Modified Internal Rate of Return (MIRR) for an investment or project. Unlike the standard Internal Rate of Return (IRR), MIRR provides a more realistic measure of profitability by explicitly accounting for the cost of financing and the reinvestment rate for cash flows. IRR controversially assumes that all positive cash flows generated by a project are reinvested at the project’s own IRR, which is often an unrealistically high rate. The MIRR corrects this by allowing the user to specify a separate, more practical reinvestment rate, as well as a financing rate for any negative cash flows that occur after the initial investment.

This calculator is essential for financial analysts, corporate planners, and real estate investors who need a more accurate assessment of a project’s viability. It resolves two major drawbacks of the traditional IRR: the multiple-IRR problem for projects with non-conventional cash flows (alternating positive and negative flows) and the unrealistic reinvestment rate assumption.

The Modified IRR (MIRR) Formula and Explanation

The MIRR is the discount rate that equates the present value of a project’s cash outflows with the future value of its cash inflows. The formula is as follows:

MIRR = ( FV (Positive Cash Flows, Reinvestment Rate) / PV (Negative Cash Flows, Financing Rate) )^(1/n) – 1

This formula may seem complex, but it’s a logical process of bringing all costs to the present and all returns to the future before calculating a single rate of return.

Variables Table

Variable	Meaning	Unit	Typical Range
FV	Future Value of all positive cash inflows, compounded at the reinvestment rate.	Currency ($)	Varies
PV	Present Value of all negative cash outflows (including initial investment), discounted at the financing rate.	Currency ($)	Varies
n	The total number of periods in the project’s life.	Time (Years/Months)	1 – 30
Reinvestment Rate	The rate at which positive cash flows can be reinvested externally.	Percentage (%)	2% – 15%
Financing Rate	The cost of capital used to fund the project’s negative cash flows.	Percentage (%)	2% – 15%

For more detailed capital budgeting techniques, consider learning about net present value (npv) analysis.

Practical Examples

Example 1: Tech Startup Investment

An investor is considering a $250,000 investment in a startup. They expect no returns in Year 1, but then anticipate cash flows of $50,000, $100,000, $150,000, and $200,000 in Years 2 through 5. The investor’s financing rate (cost of capital) is 12%, and they can reinvest returns into other ventures at a conservative 7%.

• Inputs:
  • Initial Investment: $250,000
  • Cash Flows: 0, 50000, 100000, 150000, 200000
  • Reinvestment Rate: 7%
  • Financing Rate: 12%
• Results:
  • Future Value of Inflows: $623,088
  • Present Value of Outflows: $250,000
  • MIRR: 20.02%

This MIRR suggests the project is highly attractive, exceeding the 12% cost of capital. You can compare this to other capital budgeting techniques to get a full picture.

Example 2: Real Estate Development with an Outflow

A developer acquires land for $500,000. Expected cash flows are $100,000 in Year 1 and $200,000 in Year 2. However, in Year 3, a major renovation costs $50,000 (a negative cash flow). In Years 4 and 5, flows are $300,000 and $400,000. The financing rate is 9%, and the reinvestment rate is 6%.

• Inputs:
  • Initial Investment: $500,000
  • Cash Flows: 100000, 200000, -50000, 300000, 400000
  • Reinvestment Rate: 6%
  • Financing Rate: 9%
• Results:
  • Future Value of Inflows: $1,208,090
  • Present Value of Outflows: $538,612 (Initial investment + PV of Year 3 outflow)
  • MIRR: 17.55%

Understanding the difference in irr vs mirr is crucial for accurate project profitability analysis.

How to Use This Modified IRR Calculator

1. Enter Initial Investment: Input the total upfront cost of the project as a positive value.
2. Input Periodic Cash Flows: Provide the series of cash flows in the textarea, separated by commas. These are the net cash flows for each period (e.g., year). Use negative numbers for periods with a net cash outflow.
3. Set Reinvestment Rate: Specify the annual rate at which you assume positive cash flows will be reinvested. This is often a conservative market rate or the company’s average return on other investments.
4. Set Financing Rate: Enter the interest rate the company pays on its capital (its WACC or cost of debt). This rate is used to discount all negative cash flows to their present value.
5. Analyze the Results: The calculator instantly provides the MIRR. A result higher than your financing rate generally indicates a profitable project. The intermediate values (PV of outflows, FV of inflows) help you understand how the final MIRR was derived.

Key Factors That Affect MIRR

• Reinvestment Rate: A higher reinvestment rate assumption will increase the future value of inflows, directly boosting the MIRR. This is one of the most sensitive inputs.
• Financing Rate: A higher financing rate increases the present value of any intermediate negative cash flows, which in turn lowers the MIRR.
• Timing of Cash Flows: Cash flows received earlier have more time to be reinvested, leading to a higher future value and a higher MIRR. Large cash flows at the end of a project’s life have less impact.
• Magnitude of Cash Flows: Larger positive cash flows will naturally increase the MIRR, while larger negative cash flows will decrease it.
• Project Duration (n): A longer project gives more periods for compounding, but the per-period return (MIRR) can be lower for long-term projects compared to short-term ones with the same total return.
• Initial Investment Size: A smaller initial investment relative to the inflows will result in a higher MIRR, indicating greater capital efficiency.

Frequently Asked Questions (FAQ)

1. Why is MIRR better than IRR?

MIRR is generally considered superior because it uses a more realistic reinvestment rate for cash flows and avoids the multiple-IRR problem that can occur with projects having non-conventional cash flows.

2. What is a good MIRR?

A “good” MIRR is one that is higher than the project’s financing rate (or cost of capital). If MIRR > Financing Rate, the project is expected to create value.

3. Can MIRR be negative?

Yes, a negative MIRR indicates that the project is expected to lose money. This happens when the future value of all positive cash flows is less than the present value of all negative cash flows.

4. What should I use for the reinvestment rate?

A common practice is to use the company’s Weighted Average Cost of Capital (WACC) or a conservative rate achievable in the market, such as the interest on treasury bonds or a money market account.

5. What is the difference between the financing rate and reinvestment rate?

The financing rate is the cost to borrow funds or the cost of capital. The reinvestment rate is the return you can earn on the cash generated by the project. In most real-world scenarios, these rates are different.

6. How does this modified IRR calculator handle multiple negative cash flows?

It correctly handles them by discounting each negative cash flow (those occurring after period 0) back to the present value at the specified financing rate and adding it to the initial investment to get the total PV of outflows.

7. Does MIRR work for any project?

MIRR is most useful for projects with both positive and negative cash flows over their lifetime, a common scenario in complex project profitability analysis. For simple investments with one outflow and one inflow, IRR and MIRR will yield similar results.

8. What’s the relationship between MIRR and NPV?

Both are methods of discounted cash flow dcf analysis. If a project’s MIRR is greater than its financing rate, its Net Present Value (NPV) will be positive when discounted at that same financing rate. They usually lead to the same accept/reject decision.