What is IRR and how is it calculated?

IRR (Internal Rate of Return) is the discount rate at which the net present value (NPV) of a project's cash flows equals zero. It represents the project's break-even rate of return. IRR cannot be solved algebraically — it requires iterative numerical methods like Newton-Raphson or bisection. Our IRR calculator runs Newton-Raphson with a bisection fallback for guaranteed convergence.

How do I use this IRR calculator?

Enter (1) the initial investment (positive number, treated as outflow), (2) yearly cash flows separated by commas, and (3) your hurdle rate (required rate of return). The calculator instantly computes IRR, NPV at the hurdle rate, profitability index, and gives an accept/reject decision based on IRR vs hurdle.

What is the difference between IRR and NPV?

NPV gives you a dollar value at a specific discount rate; IRR gives you the discount rate at which NPV = 0. NPV measures absolute value creation in dollars. IRR measures rate of return as a percentage. For independent conventional projects, both give the same accept/reject decision. For mutually exclusive projects (you can only pick one), NPV is more reliable because IRR can mislead with different scales or non-conventional cash flows.

A 'good' IRR is one that exceeds your hurdle rate (cost of capital or required return). Typical benchmarks: corporate WACC is 8-12%, so projects with IRR > 12% are usually accepted. Real estate targets 10-15% IRR. Private equity and venture capital often target 20-30%+. Always compare IRR to your specific hurdle rate, not to absolute benchmarks.

Yes. If the project's cash flows don't cover the initial investment (in present value terms at any rate), IRR is negative. A negative IRR means the project loses value at every positive discount rate. Always reject projects with negative IRR (unless they're strategic investments where the analysis ignores some benefit).

Why does IRR sometimes give multiple answers?

Non-conventional cash flows (multiple sign changes — e.g. negative, positive, negative, positive) can produce multiple mathematical IRRs that all satisfy NPV = 0. This is a known limitation of IRR. When this happens, use NPV with your specific discount rate, or use Modified IRR (MIRR) which assumes a specific reinvestment rate. For most conventional projects (one initial outflow followed by inflows), IRR is unique.

What is the IRR reinvestment assumption?

IRR implicitly assumes that interim cash flows are reinvested at the IRR rate — which is often unrealistic. For example, a project with 30% IRR assumes you can reinvest every interim cash flow at 30%, which is rarely possible. This is why high IRRs can be misleading. Modified IRR (MIRR) addresses this by using a separate reinvestment rate, typically the cost of capital.

Is IRR used in private equity?

Yes — IRR is the dominant return metric in private equity, venture capital, and real estate. PE funds quote 'gross IRR' (before fees) and 'net IRR' (after fees) for their portfolio companies and overall fund performance. Top-quartile PE funds typically deliver 20-25% net IRR over a 10-year fund life. However, MOIC (multiple on invested capital) is often quoted alongside IRR to give a complete picture.

IRR Calculator

The Internal Rate of Return (IRR) is the discount rate at which a project's NPV equals zero — in other words, the project's break-even discount rate. If IRR exceeds your required rate of return (hurdle rate), the project creates value and should be accepted. IRR is solved iteratively using Newton-Raphson with bisection fallback. Our IRR calculator handles any number of irregular cash flows, computes the corresponding NPV at your hurdle rate, profitability index, and provides a side-by-side comparison so you can see exactly how IRR and NPV interact. Use it for capital budgeting, private equity returns, real estate analysis, or any cash-flow investment decision.

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calendar_today Updated: October 2025

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New

tune Project Inputs

Initial Investment

Upfront cost (cash outflow at year 0)

Hurdle Rate 10%

0% 20% 40%

Yearly Cash Flows

trending_up Results

Internal Rate of Return

25.7516%

IRR vs Hurdle

25.75% vs 10.00%

Spread: +15.75%

NPV at Hurdle

$48,033

Profitability Idx

1.4803

Sum of CFs

$200,000

Net Cash Flow

+$100,000

tips_and_updates Tips

• Accept the project when IRR > hurdle rate; reject when IRR < hurdle rate
• IRR and NPV always agree on accept/reject for conventional projects (one initial outflow, then inflows)
• For mutually exclusive projects, prefer NPV — IRR can mislead with different scales or timing
• Multiple sign changes in cash flows can produce multiple IRRs (use modified IRR or NPV instead)
• IRR assumes interim cash flows are reinvested at the IRR rate — often unrealistic for high IRRs
• Private equity and VC commonly target IRRs of 20-30%+
• A higher IRR is always better when comparing similar projects with similar scales

info

Financial disclaimer. This calculator provides estimates for informational and educational purposes only and is not financial, investment, tax or legal advice. Results depend on assumptions that may not match your situation. Before making a financial decision, consult a licensed financial advisor, mortgage broker, accountant or attorney about your specific circumstances.

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Formulas sourced from regulatory and industry authorities

Last updated October 2025

Formulas, assumptions and benchmarks reference Investopedia - IRR and CFA Institute.

How to Use This Calculator

Enter initial investment

Upfront cost of the project (treated as a cash outflow at time 0).

Set hurdle rate

Your required rate of return — the bar IRR must clear to accept the project.

Enter cash flows

Comma-separated yearly cash inflows. Add as many years as needed.

Read IRR

See the IRR percentage, accept/reject decision, NPV at your hurdle rate, and profitability index.

Compare to NPV

Both NPV and IRR are shown — use NPV for mutually exclusive projects, IRR for hurdle-based decisions.

The Formula

IRR is the rate of return implied by a project's cash flows — it cannot be solved algebraically and requires iterative numerical methods (Newton-Raphson, bisection). Our calculator runs Newton-Raphson with a bisection fallback to guarantee convergence even for unusual cash flow patterns. Once you have IRR, the decision rule is simple: if IRR > your hurdle rate (cost of capital), accept the project; if IRR < hurdle rate, reject it.

0 = -Initial + Σ CF_t / (1 + IRR)^t solve for IRR

lightbulb Variables Explained

IRR Internal rate of return — the discount rate at which NPV = 0
Initial Initial investment (cash outflow at t=0)
CF_t Cash flow in period t
t Period number (1, 2, 3, ..., n)
n Total number of periods

tips_and_updates Pro Tips

Accept the project when IRR > hurdle rate; reject when IRR < hurdle rate

IRR and NPV always agree on accept/reject for conventional projects (one initial outflow, then inflows)

For mutually exclusive projects, prefer NPV — IRR can mislead with different scales or timing

Multiple sign changes in cash flows can produce multiple IRRs (use modified IRR or NPV instead)

IRR assumes interim cash flows are reinvested at the IRR rate — often unrealistic for high IRRs

Private equity and VC commonly target IRRs of 20-30%+

A higher IRR is always better when comparing similar projects with similar scales

The internal rate of return (IRR) is one of the most widely used metrics in corporate finance, private equity, and real estate for evaluating whether an investment is worth pursuing. Mathematically, IRR is the discount rate that makes the net present value (NPV) of all cash flows — both inflows and outflows — equal to zero. In practical terms, it represents the annualized effective compounded return rate the investment is expected to generate. If a project's IRR exceeds your hurdle rate (minimum required return), the project creates value and should be accepted; if it falls below, the project destroys value. IRR is particularly useful for comparing investments of different sizes and durations on a level playing field. A $50,000 investment returning $70,000 in 3 years has an IRR of about 11.9%, which you can directly compare against a $200,000 investment returning $280,000 in 4 years (IRR of about 8.8%). However, IRR has well-known limitations: it assumes interim cash flows are reinvested at the IRR itself (often unrealistic for high-IRR projects), and it can produce multiple solutions when cash flows alternate between positive and negative. For these cases, modified IRR (MIRR) or NPV analysis provides a more reliable answer.

Why IRR is intuitive but tricky

IRR's appeal is intuitive: it tells you the rate of return your project earns, expressed as a single percentage you can compare directly to your cost of capital or alternative investments. It's the metric every entrepreneur and venture capitalist quotes. But IRR has subtle traps: it assumes interim cash flows reinvest at the IRR itself (unrealistic for high rates), it can produce multiple values when cash flows alternate signs, and it can lead to wrong conclusions when comparing mutually exclusive projects of different scales. For most decisions, compute both IRR and NPV and let them confirm each other.

IRR vs MIRR

Modified IRR (MIRR) addresses two of IRR's main weaknesses: the unrealistic reinvestment assumption and the multiple-IRR problem. MIRR explicitly separates the financing rate (used to discount outflows) from the reinvestment rate (used to compound inflows), then computes a single rate that equates them at the project's end. MIRR is always unique and is generally more conservative than IRR. For private equity and corporate finance, IRR remains dominant, but MIRR is gaining traction as a more honest measure.

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