Internal Rate of Return Calculator

Compute IRR, MIRR (Modified Internal Rate of Return), and NPV. Visualize the NPV curve, analyze sensitivity, and get expert financial insights. Ideal for capital budgeting, private equity, and academic use.

Cash Flow Timeline

Enter cash flows for each period. Typically period 0 = initial investment (negative), and positive inflows for subsequent years. Click to add more periods.

PeriodCash Flow Amount ($)Actions
? Standard Project (-10k, +3k, +4k, +5k)
? Tech Startup (-50k, +15k, +20k, +25k, +30k)
⚠️ Multiple IRR (-100, +230, -132)
? High Return (-5k, +2k, +4k, +5k)
%
Used to compute NPV at custom rate
%
Rate for positive cash flows reinvestment
%
Cost of capital (discount for negatives)
Privacy assured: All calculations happen locally in your browser. No cash flow data is transmitted.

Understanding Internal Rate of Return (IRR) & MIRR

Internal Rate of Return (IRR) is the discount rate that makes the net present value (NPV) of all cash flows from a project equal to zero. In essence, it represents the annualized effective compounded return rate. For investors, if the IRR exceeds the cost of capital, the project is considered financially attractive. The IRR is one of the most widely used metrics in capital budgeting, real estate, private equity, and corporate finance.

NPV = Σt=0n CFt / (1 + IRR)t = 0

where CFt = cash flow at period t, and n = total periods.

Modified Internal Rate of Return (MIRR) improves upon IRR by assuming reinvestment of positive cash flows at a realistic reinvestment rate (often WACC) and financing negative cash flows at a finance rate. It provides a single, unambiguous rate and eliminates the multiple IRR problem. Formula:

MIRR = (FVpositive / PVnegative)1/n - 1

Why use an IRR & MIRR Visual Tool?

  • Quick Investment Screening: Compare multiple projects with different cash flow patterns.
  • NPV Profile Sensitivity: See how changing discount rates affect project value.
  • Multiple IRR Detection: Our algorithm warns when cash flows change signs more than once; MIRR gives a reliable metric in those cases.
  • Educational Clarity: Understand the relationship between discount rates and project viability through interactive charting.

Calculation Methodology & Reliability

The IRR is computed using a hybrid numerical method: first, a Newton-Raphson iteration (derivative-based) starting from a guess of 10%; if divergence occurs, a robust Brent-Dekker bracketing method (bisection + inverse quadratic interpolation) ensures convergence within 1×10⁻⁸ accuracy. MIRR is calculated exactly using the reinvestment and finance rates you specify. NPV is computed via exact discounted cash flow formula.

References: Brealey, R., Myers, S., & Allen, F. (2020). Principles of Corporate Finance. McGraw-Hill; CFA Institute (2023). Discounted Cash Flow Applications; Damodaran, A. (2022). Investment Valuation.

Case Study: Renewable Energy Project

A solar farm requires an initial investment of $2.5M (Year 0). Expected annual after-tax cash flows: Year 1: $500k, Year 2: $700k, Year 3: $900k, Year 4: $1.1M. The company’s WACC is 8%. Using this IRR calculator, the IRR is 16.3% which exceeds the cost of capital, indicating a positive NPV. The MIRR (with reinvestment=8%) is ~13.9%, confirming value creation. Decision: Accept the project.

Limitations & Professional Warnings

  • Multiple IRRs: If cash flows change sign more than once, there may be multiple IRRs — always analyze NPV profile and consider MIRR.
  • Reinvestment Assumption: IRR assumes reinvestment at the IRR rate, which may be unrealistic; MIRR solves this by allowing a custom reinvestment rate.
  • Mutually Exclusive Projects: IRR can conflict with NPV; use NPV as primary criterion when ranking projects.
  • No IRR exists: For all-negative or all-positive cash flows, IRR is undefined; the tool will alert.

Step‑by‑Step Usage Guide

  1. Define cash flows: Period 0 is typically the initial outlay (enter negative value). Add more rows as needed.
  2. Set discount rate (for NPV) and optionally adjust MIRR reinvestment/finance rates (defaults to discount rate).
  3. Click Calculate All to compute IRR, NPV, MIRR, and view the NPV profile chart.
  4. Use preset examples to explore different scenarios: standard, unconventional flows, and high-growth startups.
  5. Copy results for reports using the copy button.

Frequently Asked Questions

A good IRR depends on the cost of capital and industry risk. Generally, if IRR > hurdle rate (e.g., WACC), the project adds value. For venture capital, target IRR can be 25%+. For stable utilities, 8–12% is acceptable.

Yes, a negative IRR means the project loses value — the present value of costs exceeds benefits at any positive rate.

That indicates non-conventional cash flows with sign changes; the IRR equation may have more than one solution. In such cases, MIRR provides a more reliable metric.

The iterative solver provides precision up to 0.000001% (1e-8 relative error), suitable for professional financial analysis.

IRR assumes reinvestment at the IRR itself, often unrealistic. MIRR allows separate reinvestment and finance rates, providing a more conservative and realistic rate of return.
Developed by getzenquery Tech team & validated against Microsoft Excel's IRR and MIRR functions. Last updated: March 2026.