IRR Calculator

Calculate the Internal Rate of Return for an investment using Newton-Raphson iteration.

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Initial Investment (Year 0)

This will be treated as a negative cash flow

Annual Cash Flows

Internal Rate of Return

Annualized return on investment

Total Cash Inflows

Sum of all positive CFs

Net Profit

Total CFs − Investment

Payback Period

—

Years to recoup investment

Total Years

Number of cash flow periods

NPV at Various Discount Rates

Discount Rate	NPV	Decision

Calculate the Internal Rate of Return for a series of cash flows using Newton-Raphson iteration, along with payback period and NPV at several discount rates.

How It Works

How IRR Calculator Works

IRR is the discount rate at which the Net Present Value (NPV) of a series of cash flows equals exactly zero. Since there's no direct algebraic formula to solve for it, the calculator uses Newton-Raphson iteration — starting from an initial guess, repeatedly refining the rate based on how far NPV is from zero and how sensitive NPV is to a rate change, until it converges on the answer.

Your initial investment is treated as a negative cash flow at time zero, and each subsequent year's cash flow is discounted back using NPV = Σ CFₜ ÷ (1+r)ᵗ. The IRR that satisfies this equation represents the annualized rate of return the investment actually generates, accounting for both the timing and size of each cash flow.

The NPV table shows how the same cash flow series performs at several common discount rates (5% to 15%) — a positive NPV at your required rate of return signals the investment clears your hurdle rate, while a negative NPV signals it falls short, which is often used alongside IRR as a second decision check.

Worked Example

See It In Action

An investment of $100,000 generating cash flows of $20,000, $25,000, $30,000, $35,000, and $40,000 over the next five years produces an IRR of about 13.45%. Total cash inflows over the period are $150,000, for a net profit of $50,000 — and since 13.45% exceeds common hurdle rates like 10% or 12%, the NPV at those discount rates is positive, signaling the investment clears those return thresholds.

Real-World Use Cases

Who Uses IRR Calculator and Why

Evaluating a business investment or project with an upfront cost and a series of expected future cash inflows.
Comparing a calculated IRR against your required rate of return (hurdle rate) to decide whether an investment clears the bar.
Checking NPV at several common discount rates to see how sensitive an investment\'s attractiveness is to your assumed rate.
Comparing the payback period alongside IRR to weigh both how profitable and how quickly capital-recovering an investment is.

Common Mistakes

Mistakes to Avoid

Treating IRR as a simple average return — it explicitly accounts for the timing of each cash flow, not just the total, so two investments with the same total return but different cash flow timing can have meaningfully different IRRs.
Comparing IRR across investments without also considering risk — a higher IRR doesn\'t automatically mean a better investment if it comes with substantially higher risk; the hurdle rate you compare against should reflect that risk.
Forgetting the initial investment is treated as a negative cash flow at time zero — leaving it out, or entering it as a positive number, will produce a meaningless or wildly incorrect IRR result.

Pro Tips

Tips for Best Results

Use the NPV table at several discount rates as a second check alongside IRR, especially for cash flow series where IRR alone might be less intuitive to interpret.
If two projects have similar IRRs, the payback period shown alongside it can help distinguish which one returns your capital faster, which matters if liquidity or risk timing is a concern.

Troubleshooting

Fixing Common Problems

My IRR result seems too high or unrealistic. — Double check that your initial investment is entered as a negative value and that every cash flow is in the correct year and sign — a sign or ordering error in the cash flow series is the most common cause of an IRR result that looks off.

Glossary

Terms Explained

IRR (Internal Rate of Return): The discount rate at which the Net Present Value of a series of cash flows equals exactly zero.

Hurdle rate: Your required minimum rate of return for an investment to be considered worthwhile — compared against the calculated IRR to judge whether a project clears the bar.

FAQ

Frequently Asked Questions

What does a "good" IRR look like?

It depends on your required rate of return (hurdle rate) and the risk of the investment — an IRR above your hurdle rate generally signals the investment is worthwhile, while an IRR below it suggests passing. Riskier investments typically warrant a higher required IRR.

How is IRR different from a simple return percentage?

IRR accounts for the timing of cash flows, not just their total — a dollar received sooner is worth more than a dollar received later, and IRR captures that time-value effect in a way a simple total-return percentage cannot.

Why does this calculator use Newton-Raphson iteration?

Because IRR has no closed-form algebraic solution for cash flow series with more than a couple of periods — Newton-Raphson numerically converges on the rate where NPV equals zero through repeated approximation.

What is the payback period shown alongside IRR?

It's the number of years it takes for cumulative cash inflows to fully recover the initial investment, ignoring the time value of money — a simpler, complementary metric to IRR that's useful for gauging how quickly capital is returned.