Internal Rate of Return (IRR)

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What is Internal Rate of Return (IRR)?

The Internal Rate of Return (IRR) is the discount rate at which the net present value (NPV) of all cash flows from an investment equals exactly zero. Put simply: it is the implied annual return embedded in a project's cash flow schedule. If you invest $100,000 today and receive $40,000, $40,000, and $40,000 over the next three years, IRR is the single annual rate that makes those future receipts worth exactly $100,000 in present-value terms.

IRR has no closed-form algebraic solution for most real-world cash flow schedules - it must be found by numerical iteration. Spreadsheets (Excel IRR function) and financial calculators do this automatically by guessing a rate, computing NPV, and adjusting until NPV reaches zero. This iterative nature is why IRR cannot easily be back-of-envelope calculated for complex projects.

The decision rule is straightforward: if IRR exceeds the project's hurdle rate (the minimum required return, often the company's weighted average cost of capital), the investment creates value and should be accepted. If IRR falls below the hurdle rate, the project destroys value. When ranking competing projects, higher IRR is generally preferable - but this breaks down when projects differ significantly in scale, duration, or have unusual cash flow patterns.

When to use Internal Rate of Return (IRR)

Use IRR when evaluating a single project against a known hurdle rate, or comparing projects with similar scale and time horizon. It is the standard return language in private equity and venture capital: when a fund reports a "25% net IRR," it means that 25% annually is the rate at which the timing-adjusted value of all capital contributions and distributions break even. Pair IRR with MOIC to capture both the efficiency (IRR) and the magnitude (MOIC) of returns. Do not rely on IRR alone when comparing projects of very different sizes - a 40% IRR on $100K may generate far less value than a 20% IRR on $5M.

Worked examples for Internal Rate of Return (IRR)

This table quickly gives you the overview you need to understand Internal Rate of Return (IRR) and its most important comparisons.

Common pitfalls

IRR has two well-known failure modes. First, multiple IRRs: if a project has alternating positive and negative cash flows - for example a mine that generates cash for years, then requires expensive environmental remediation at closure - the underlying polynomial can have multiple solutions, making IRR ambiguous. Second, the reinvestment rate assumption: IRR implicitly assumes interim cash flows are reinvested at the IRR rate itself, which is unrealistic for high-IRR projects. In both cases, Modified IRR (MIRR) or NPV is more reliable.

Frequently asked questions about Internal Rate of Return (IRR)

What is the difference between IRR and NPV?

NPV expresses investment value as an absolute dollar figure at a chosen discount rate. IRR is the specific discount rate at which NPV equals zero - it is a percentage, not a dollar amount. For a standard project (cash out then cash in), the two methods agree: if IRR > hurdle rate, NPV at that hurdle rate is positive. They can disagree when ranking competing projects of different scale or timing - in those cases, NPV is more reliable.

What is a good IRR?

It depends on the asset class and risk. Private equity funds typically target 20-30% gross IRR. Venture capital funds may target 30%+ to compensate for portfolio company failures. Corporate investment projects are often evaluated against the company's WACC, typically 8-15%. Real estate deals commonly target 12-20% IRR depending on risk profile. The only valid benchmark is the opportunity cost: what else can the capital earn at the same risk level?

What is a hurdle rate?

A hurdle rate is the minimum acceptable IRR for an investment. In corporate finance it is typically the company's WACC plus a risk premium. In private equity it is a contractual threshold (commonly 8%) above which the fund manager earns carried interest. Any project with IRR below the hurdle rate is rejected because it earns less than the cost of the capital required to fund it.

Test your knowledge

Quiz: how well do you know IRR?

5 questions · ~2 min

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1. What does the Internal Rate of Return (IRR) represent?

A The expected future value of an investment, calculated by summing all projected cash inflows without discounting them back to present value B The discount rate at which the net present value of all cash flows from an investment equals exactly zero - the implied annual return embedded in a project's cash flow schedule C The ratio of total profit to initial investment, expressed as a percentage of original capital committed regardless of time period D The difference between a project's cost of capital and its weighted average return on assets, expressed in percentage points as a spread metric

ℹ The definition states IRR is the discount rate at which the NPV of all cash flows equals exactly zero. It is the implied annual return embedded in the project's cash flow schedule - if you invest $100,000 today and receive $40,000/year for 3 years, IRR is the rate that makes those future receipts worth exactly $100,000 today.

2. When do IRR and NPV agree, and when can they conflict?

A IRR and NPV always agree on both accept/reject decisions and project ranking, since they use the same cash flows and only differ in presentation format B IRR is more reliable than NPV for all comparisons because it produces a single percentage that can be compared across different investment sizes and time horizons C IRR and NPV disagree on accept/reject decisions but agree on project ranking, since the discount rate affects the dollar amount but not the implied return percentage D For a standard project both methods agree on accept/reject (IRR above hurdle = positive NPV), but they can disagree when ranking projects of different scale or timing, in which case NPV is more reliable

ℹ The FAQ states that for a standard project (cash out then cash in), if IRR exceeds the hurdle rate, NPV at that rate is positive - both methods agree. They can conflict when ranking competing projects of different scale or timing, and in those cases the FAQ says NPV is more reliable.

3. According to the examples table, which project has the highest IRR?

A Project B (back-loaded) at 14.5% - the three-year wait for the $150,000 payoff implies a higher annual return rate than the steadier projects B Project C (large) at 12.8% - its larger investment generates more absolute cash flow than the smaller projects C Project A (steady) at 9.7% - the consistent annual cash flows reduce risk and provide the highest risk-adjusted return D Project D (loss) because the negative cash flows create a high negative IRR that implies superior return when adjusted for risk

ℹ The examples table shows Project B (back-loaded) has an IRR of 14.5%, the highest of the four projects. Despite receiving no cash until Year 3, the single $150,000 payment on a $100,000 investment implies the highest annual compounding rate.

4. What are the two main failure modes of IRR identified in the pitfalls section?

A IRR fails when projects have different starting dates and when the hurdle rate changes over time; both are fixed by adjusting each cash flow to a common base date B IRR can produce artificially high results when costs are understated, and artificially low results when revenues are delayed beyond Year 3 of the cash flow schedule C Multiple IRRs (when cash flows alternate between positive and negative, creating an ambiguous polynomial) and the reinvestment rate assumption (interim cash flows are implicitly assumed to reinvest at the IRR rate itself); in both cases MIRR or NPV is more reliable D IRR overstates returns on large projects due to a scale bias, and understates returns on small projects because the percentage calculation amplifies small absolute gains disproportionately

ℹ The pitfalls section identifies two failure modes: first, multiple IRRs when a project has alternating positive and negative cash flows (as with a mine requiring closure remediation); second, the reinvestment rate assumption - IRR implicitly assumes interim cash flows are reinvested at the IRR rate itself, which is unrealistic for high-IRR projects.

5. According to the FAQs, what is the only valid benchmark for determining whether an IRR is "good"?

A An IRR above 20%, since below that threshold the inflation-adjusted return approaches zero and the investment destroys real value for institutional investors B The opportunity cost of capital at the same risk level - private equity may target 20-30%, venture capital 30%+, corporate projects the company's WACC (8-15%), and real estate 12-20%, so the threshold varies by asset class and risk profile C At least double the risk-free rate (10-year Treasury yield), a standard institutional benchmark to compare project returns on a risk-adjusted basis D The project's accounting return on equity (ROE), since ROE reflects the actual historical book return and represents the minimum credible new investment threshold

ℹ The FAQ states the only valid benchmark is the opportunity cost: what else can the capital earn at the same risk level? It then gives typical targets by asset class - PE 20-30%, VC 30%+, corporate WACC 8-15%, real estate 12-20% - showing there is no universal "good" IRR independent of context.

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