Internal Rate of Return (IRR) is the discount rate that makes the net present value of all cash flows from an investment equal to zero. Practically, it's the implied annualized return rate of an investment given its specific cash flow schedule. If you invest $100,000 today and receive cash flows totaling more than $100,000 spread over future years, the IRR tells you the equivalent steady annual rate.

How is IRR different from ROI?

ROI is total return as a percentage of initial investment, without accounting for time. IRR is annualized and accounts for when cash flows occur. A 30% ROI over 2 years has an IRR of ~14%; the same 30% ROI over 10 years has an IRR of ~2.7%. IRR is the right tool when comparing investments with different time horizons.

A "good" IRR is one that exceeds your hurdle rate — the minimum return you require to compensate for the risk. For typical equity investments, 10–15% is often considered acceptable. For real estate, 12–20% is common. For private equity and venture, hurdle rates often run 15–25%+. Risky investments should produce higher IRRs to compensate for the additional risk.

Can IRR have multiple values?

Yes — when cash flows change sign more than once (e.g., investment, positive returns, then another investment), the IRR equation can have multiple valid mathematical solutions. In those cases, use NPV calculated at a specific discount rate instead — it always has a single, unambiguous answer.

How is IRR calculated?

IRR has no closed-form solution — it's found numerically, typically by Newton-Raphson iteration. The algorithm starts with an initial guess (often 10%), evaluates NPV at that rate, and adjusts the guess based on the slope until NPV is approximately zero. Modern calculators and spreadsheets (Excel's =IRR function) handle this in milliseconds.

IRR Calculator

Calculate the internal rate of return (IRR) for an investment using an iterative Newton-Raphson solver. Enter your initial investment and up to 10 years of expected cash flows to find the discount rate that makes the net present value equal to zero.

Last updated: July 28, 2026Reviewed by the CalcMountain editorial team

About this calculator

Internal Rate of Return (IRR) is the discount rate at which an investment's net present value (NPV) equals zero — equivalently, the implied annualized return of an investment's cash flow stream. If you invest $100,000 today and receive specific cash flows over the next 5 years, the IRR is the single annual rate that exactly balances the upfront cost against the present value of all future cash flows.

The metric is everywhere in serious investing: private equity LPs evaluate fund managers on IRR, real estate investors quote IRR on deals, corporate finance teams use it for capital budgeting (project A IRR 18% vs project B IRR 12%), and venture investors track IRR across their portfolios. IRR is the natural metric whenever cash flows are irregular — multiple deposits, withdrawals, or returns happening at different points in time — because simpler measures like CAGR can't handle that complexity.

This calculator uses Newton-Raphson iteration to solve for the IRR given an initial investment and up to 5 years of cash flows. The output is a single annualized return. Use it for project evaluation, real estate deal analysis, comparing investment alternatives with different timing, and stress-testing assumptions. The result is meaningful only when compared to your hurdle rate (the minimum return you require to make the investment worthwhile) — an IRR of 14% is great if your hurdle rate is 10% and mediocre if your hurdle rate is 18%.

Formula

Internal Rate of Return is defined implicitly as the discount rate r that solves: NPV = 0 = −C₀ + Σ [t=1 to T] CF(t) / (1 + r)^t Where: C₀ = Initial investment (entered as a positive number; treated as negative in the equation) CF(t) = Cash flow received at the end of year t T = Number of years r = IRR (the unknown we're solving for) There is no closed-form solution; IRR is found numerically. Newton-Raphson iteration: Start with an initial guess r₀ (commonly 10%). Iterate: r_new = r_old − NPV(r_old) / NPV'(r_old) Repeat until |NPV(r)| < small tolerance (typically < $0.01). Where NPV'(r) is the derivative: NPV'(r) = −Σ [t=1 to T] t × CF(t) / (1 + r)^(t+1) Newton-Raphson typically converges in 5–10 iterations. Relationship to NPV: If IRR > hurdle rate: NPV at hurdle rate is positive → invest. If IRR < hurdle rate: NPV at hurdle rate is negative → reject. If IRR = hurdle rate: NPV = 0 → indifferent. Example: Invest $100,000. Receive $20,000, $25,000, $30,000, $35,000, $40,000 over 5 years. Solving for IRR (numerically): At r = 10%: NPV = 12,170 (positive, IRR > 10%) At r = 14%: NPV = 1,860 (positive, IRR > 14%) At r = 14.85%: NPV ≈ 0 (converged) IRR ≈ 14.85% per year. Equivalently: an investment in the same risk class needs to return 14.85% per year compounded to match this opportunity.

How to use this calculator

Enter the initial investment as a positive number — the amount of cash committed at time zero.
Enter each subsequent year's expected cash flow. Positive numbers represent income or distributions to you; negative numbers represent additional capital calls. Most simple projects have all-positive cash flows after year 0.
Review the IRR. It's the single annualized rate the project effectively pays you over its life.
Compare IRR to your hurdle rate (the minimum return you require). If IRR > hurdle, the project creates value at your required return. If IRR < hurdle, walk away.
For real estate or business-deal analysis, ensure cash flows include both operating cash flow each year AND the terminal sale/exit value in the final year (which often dominates the IRR).
For sensitivity, rerun with conservative cash flow assumptions (lower revenues, higher expenses, lower exit value) to see how robust the IRR is. Deals that only work under optimistic assumptions usually don't.
For projects with non-conventional cash flows (multiple sign changes — e.g., requiring additional investment in year 3), be aware that IRR can have multiple valid solutions. Use NPV at your specific hurdle rate instead in those cases.

Worked examples

Real estate flip — 18-month timeline

Buy property for $200,000 in cash. Renovation costs $50,000 in year 1. Sell for $310,000 in year 2 (18 months). Initial investment: $200,000 Year 1 cash flow: −$50,000 (renovation) Year 2 cash flow: $310,000 (sale) Solving for IRR: approximately 14.5% annualized. The simple total return is ($310K − $200K − $50K) / $250K = 24% — but that ignores the time value. IRR correctly accounts for the renovation occurring a year later and gives the annualized rate.

Small business buyout — 5-year hold

Buy a small business for $500,000. Operating cash flows: $80K, $100K, $120K, $140K, $160K. Sell business at end of year 5 for $750,000. Initial investment: $500,000 Year 1: $80,000 Year 2: $100,000 Year 3: $120,000 Year 4: $140,000 Year 5: $160,000 + $750,000 = $910,000 Solving for IRR: approximately 26% annualized. A strong return if achievable. The terminal sale value dominates — IRR drops dramatically if the exit comes in at $500K (no appreciation) instead of $750K.

Comparing two projects of different lengths

Project A: Invest $100K, returns $130K in year 2. Total return 30%, time 2 years. Project B: Invest $100K, returns $200K in year 5. Total return 100%, time 5 years. Project A IRR: (130/100)^(1/2) − 1 ≈ 14.0% Project B IRR: (200/100)^(1/5) − 1 ≈ 14.9% Despite Project B having far higher total return, the IRRs are within 1% of each other. Without time-adjusting via IRR, Project B looks far better; properly compared, they're nearly equivalent annualized returns.

When to use this calculator

Use this calculator for any investment with cash flows occurring at multiple points in time — real estate deals (purchase + operating cash flow + sale proceeds), business buyouts (purchase + operating + exit), corporate capital projects (investment + ramp + steady-state cash flow), and private investment positions where capital calls and distributions happen at different times.

IRR is the right tool when you need a single annualized return number that handles irregular cash flows. CAGR handles only beginning-and-ending values with nothing in between; IRR handles arbitrary cash flow schedules. NPV handles the same cash flows but requires a discount rate as input rather than producing one.

Pair this with the NPV calculator (its mirror — given a discount rate, find the value; IRR is the discount rate that makes value zero), the ROI calculator (simpler total-return measure, not time-adjusted), and the CAGR calculator (when there are no intermediate cash flows).

A few caveats: IRR assumes interim cash flows are reinvested at the IRR — a strong assumption that's often not realistic. For more accurate ranking of competing projects, look at NPV at a specific hurdle rate or Modified Internal Rate of Return (MIRR) which uses a separate reinvestment rate. IRR can also produce multiple mathematical solutions when cash flows change sign more than once (e.g., investment, returns, then another investment) — in those cases, fall back to NPV.

For everyday investment analysis, IRR is the standard. For PE, VC, and real estate, IRR is the industry-standard performance metric. Knowing how to read it correctly — and what its limitations are — separates serious investment analysis from amateur work.

Common mistakes to avoid

Comparing IRRs from projects of different lengths without context. A 5-year project IRR and a 2-year project IRR are both annualized, so technically comparable — but the longer project's IRR depends on more years of cash flow assumptions and is more uncertain.
Ignoring the reinvestment assumption. IRR assumes cash flows can be reinvested at the IRR. If your IRR is 25% but your realistic reinvestment opportunity is 7%, the actual realized return on the entire dollar stream will be lower. Modified IRR (MIRR) addresses this by allowing a separate reinvestment rate.
Falling for high IRRs on small deals. A small deal with a 50% IRR and total profit of $10K is less valuable than a large deal with 15% IRR and total profit of $500K. IRR doesn't capture absolute dollar return — combine it with NPV or total profit for the complete picture.
Forgetting that IRR is annualized. If your investment makes "100% return" in 6 months, the IRR is much higher than 100% (compounded). Conversely, "100% return" in 10 years has an IRR of only ~7%.
Using IRR on cash flow streams with multiple sign changes. If cash flows go negative, positive, negative, positive, the IRR equation can have multiple solutions. Use NPV at a specific discount rate instead — it has only one answer.
Treating IRR as a quality score independent of hurdle rate. An 18% IRR is fantastic if your hurdle is 12% and unacceptable if your hurdle is 22%. Always evaluate IRR against the appropriate risk-adjusted required return.

Frequently Asked Questions

Sources & further reading

Internal Rate of Return — Capital Budgeting Concepts — U.S. Securities and Exchange Commission
Discounted Cash Flow Analysis — fundamentals — U.S. Securities and Exchange Commission
FINRA — Key Investing Concepts — Financial Industry Regulatory Authority

IRR Calculator

Inputs

Initial Investment

Year 1 Cash Flow

Year 2 Cash Flow

Year 3 Cash Flow

Year 4 Cash Flow

Year 5 Cash Flow

Results

Internal Rate of Return

13.45%

Total Cash Inflows

$150,000

Net Return

$50,000

Payback Period

3.7 years

Cash Flow Analysis

Year	Cash Flow	Cumulative	Present Value
0	$-100,000.00	$-100,000.00	$-100,000.00
1	$20,000.00	$-80,000.00	$17,628.43
2	$25,000.00	$-55,000.00	$19,422.59
3	$30,000.00	$-25,000.00	$20,543.39
4	$35,000.00	$10,000.00	$21,125.28
5	$40,000.00	$50,000.00	$21,280.31

Last updated: July 28, 2026Reviewed by the CalcMountain editorial team

About this calculator

Formula

How to use this calculator

Enter the initial investment as a positive number — the amount of cash committed at time zero.
Enter each subsequent year's expected cash flow. Positive numbers represent income or distributions to you; negative numbers represent additional capital calls. Most simple projects have all-positive cash flows after year 0.
Review the IRR. It's the single annualized rate the project effectively pays you over its life.
Compare IRR to your hurdle rate (the minimum return you require). If IRR > hurdle, the project creates value at your required return. If IRR < hurdle, walk away.
For real estate or business-deal analysis, ensure cash flows include both operating cash flow each year AND the terminal sale/exit value in the final year (which often dominates the IRR).
For sensitivity, rerun with conservative cash flow assumptions (lower revenues, higher expenses, lower exit value) to see how robust the IRR is. Deals that only work under optimistic assumptions usually don't.
For projects with non-conventional cash flows (multiple sign changes — e.g., requiring additional investment in year 3), be aware that IRR can have multiple valid solutions. Use NPV at your specific hurdle rate instead in those cases.

Worked examples

Real estate flip — 18-month timeline

Small business buyout — 5-year hold

Comparing two projects of different lengths

When to use this calculator

Common mistakes to avoid

Comparing IRRs from projects of different lengths without context. A 5-year project IRR and a 2-year project IRR are both annualized, so technically comparable — but the longer project's IRR depends on more years of cash flow assumptions and is more uncertain.
Ignoring the reinvestment assumption. IRR assumes cash flows can be reinvested at the IRR. If your IRR is 25% but your realistic reinvestment opportunity is 7%, the actual realized return on the entire dollar stream will be lower. Modified IRR (MIRR) addresses this by allowing a separate reinvestment rate.
Falling for high IRRs on small deals. A small deal with a 50% IRR and total profit of $10K is less valuable than a large deal with 15% IRR and total profit of $500K. IRR doesn't capture absolute dollar return — combine it with NPV or total profit for the complete picture.
Forgetting that IRR is annualized. If your investment makes "100% return" in 6 months, the IRR is much higher than 100% (compounded). Conversely, "100% return" in 10 years has an IRR of only ~7%.
Using IRR on cash flow streams with multiple sign changes. If cash flows go negative, positive, negative, positive, the IRR equation can have multiple solutions. Use NPV at a specific discount rate instead — it has only one answer.
Treating IRR as a quality score independent of hurdle rate. An 18% IRR is fantastic if your hurdle is 12% and unacceptable if your hurdle is 22%. Always evaluate IRR against the appropriate risk-adjusted required return.

Frequently Asked Questions

Sources & further reading

Internal Rate of Return — Capital Budgeting Concepts — U.S. Securities and Exchange Commission
Discounted Cash Flow Analysis — fundamentals — U.S. Securities and Exchange Commission
FINRA — Key Investing Concepts — Financial Industry Regulatory Authority

About this calculator

Formula

How to use this calculator

Worked examples

Real estate flip — 18-month timeline

Small business buyout — 5-year hold

Comparing two projects of different lengths

When to use this calculator

Common mistakes to avoid

Frequently Asked Questions

What is IRR?

How is IRR different from ROI?

What is a good IRR?

Can IRR have multiple values?

How is IRR calculated?

Sources & further reading

Related Calculators

NPV Calculator

ROI Calculator

DCF Calculator

Black-Scholes Calculator

Sharpe Ratio Calculator

Asset Allocation Calculator

Inputs

Results

Cash Flow Analysis

About this calculator

Formula

How to use this calculator

Worked examples

Real estate flip — 18-month timeline

Small business buyout — 5-year hold

Comparing two projects of different lengths

When to use this calculator

Common mistakes to avoid

Frequently Asked Questions

What is IRR?

How is IRR different from ROI?

What is a good IRR?

Can IRR have multiple values?

How is IRR calculated?

Sources & further reading

Related Calculators

NPV Calculator

ROI Calculator

DCF Calculator

Black-Scholes Calculator

Sharpe Ratio Calculator

Asset Allocation Calculator

Inputs

Results

Cash Flow Analysis