Internal rate of return

Spread over the hurdle rate
NPV at the hurdle rate
Total cash returned
Verdict

How it works

IRR is the discount rate at which a project’s NPV is exactly zero. It expresses the return as a single percentage, which is why boards and investment committees ask for it even though NPV is the more reliable measure.

Compare it against your hurdle rate: above it the project earns more than your cost of capital, below it the capital is better used elsewhere. The gap between the two is the margin of safety on the investment.

Find r where −C₀ + Σ Cₜ ÷ (1 + r)ᵗ = 0

  • IRR — the rate at which the project exactly breaks even in present-value terms
  • Hurdle rate — the minimum return you require before committing capital
  • Spread — IRR less hurdle rate — the cushion if things go worse than planned

Worked example

Investing 2,000,000 against five years of cashflows, with a 12% hurdle

Inputs

Investment2,000,000
Flows450k, 520k, 610k, 680k, 740k
Hurdle12%

Results

IRR13.9%
Spread over hurdle+1.9 pts
NPV at hurdle102,561

Clears the hurdle, but only by 1.9 points. A 15% shortfall in the final year’s cashflow would wipe that out.

Frequently asked questions

Why is there no IRR for my figures?

IRR needs the cashflows to change sign — money out, then money in. If every flow is negative, or the total never turns positive, no rate can balance the equation and the calculator says so rather than inventing a figure.

What is wrong with IRR?

Two things. It assumes intermediate cashflows are reinvested at the IRR itself, which is usually optimistic, and cashflows that change sign more than once can produce several mathematically valid answers. Use NPV as the tie-breaker.

How does IRR compare to XIRR?

IRR assumes evenly spaced periods. XIRR handles cashflows on arbitrary dates, which is what you want for a real portfolio or an irregular project.

Is my data sent anywhere?

No. The calculation runs entirely in your browser. Nothing you type is transmitted to us or stored.

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