IRR Calculator

Internal rate of return distills a whole series of cash flows — an initial outlay followed by returns spread over time — into a single percentage: the rate at which those cash flows exactly break even, neither creating nor destroying value once discounted. It answers a specific question: "what constant annual return would this investment need to deliver, given exactly when the money goes out and comes back in, to be worth exactly what was paid for it?" That makes it more informative than a simple total-return percentage, because it accounts for timing — money returned in year one is worth more than the same amount returned in year five, and IRR is sensitive to that difference in a way a plain return figure is not.

Businesses and investors typically compare a computed IRR against a hurdle rate — the minimum return they require to bother taking on the risk, often derived from their cost of capital or from what a safer alternative would return. A project whose IRR clears that hurdle is, by this measure, worth pursuing; one that falls short is not, at least not on financial grounds alone. Because it produces a percentage rather than a currency amount, IRR is also commonly used to communicate a project’s attractiveness in a way that is intuitive to compare across very differently sized opportunities, even though — as below — that convenience comes with a real limitation.

The two measures usually point the same direction but are not interchangeable, and disagreements between them are informative rather than a bug.

IRR has two well-known failure modes. The first is scale-blindness — it says nothing about how much value is actually created, only the rate at which it is created, so it can rank a tiny, high-return project above a much larger one that creates far more absolute value. The second is the possibility of multiple IRRs: when a series of cash flows changes sign more than once, for example an outlay followed by returns followed by a further cost, the underlying equation can have more than one valid solution, making a single IRR figure ambiguous or misleading. Both are reasons NPV is generally treated as the more dependable measure when the two disagree.

A hurdle rate is the minimum acceptable return a business or investor sets before committing capital, and it is rarely just "whatever a bank would pay." It is typically built up from a baseline cost of capital — what it costs the organization to raise money in the first place — with a margin added for the specific risk of the project being evaluated. A speculative venture is held to a higher hurdle than a low-risk expansion of an existing, proven business line, which is why the same nominal IRR can be an easy yes for one project and a clear no for another.