IRR (Internal Rate of Return): The Core Metric for Judging Investment Returns

If you've spent any time making financial decisions, you've almost certainly run into the term IRR, the internal rate of return. IRR is a go-to metric for evaluating the profitability of a project or investment, and because it puts expected returns in intuitive terms, it's a favorite not only of CFOs but of CEOs too.

In this piece, we'll walk through what IRR is, what it does, and how it differs from NPV (net present value).

What Is IRR?

IRR is the metric that expresses an investment's expected rate of return. Put simply, it's the return you'd internally expect to earn if you actually made the investment — and because it's more intuitive than NPV (which is built on the same discounted-cash-flow logic), it tends to resonate with CEOs even more than CFOs. By projecting the average return an investment is likely to produce, it gives you an intuitive way to compare competing options. A higher IRR signals higher profitability, letting you quickly size up which of several investments looks most attractive.

How NPV (Net Present Value) and IRR Relate

To understand IRR, you first have to understand NPV (net present value). NPV is the value you get when you discount an investment's future cash flows back to today and subtract the initial outlay. A positive NPV means the investment creates value; a negative NPV means the opposite. NPV is the metric that shows clearly how much monetary value an investment actually creates.

IRR is the discount rate at which NPV equals zero.

For example, an IRR of 10% is the prediction that the investment project will generate a 10% return each year.

Now suppose your company's target return is 8%. Since this project is expected to return 10%, it clears the target — so it can be judged favorably as meeting the company's expectations.

Conversely, if your company's target return were 12%, this project would fall short of the hurdle and might warrant a second look.

That's how IRR works as a useful metric: by stacking it up against your target return to gauge an investment's appeal.

The Pros and Cons of IRR

Where IRR Shines

• Intuitive to grasp: Because it's expressed as a percentage return, even non-specialists can understand it easily.

• Direct comparison to cost of capital: You can weigh it against your cost of capital or target return to make a quick call on whether to invest.

• Simpler decision-making: It distills complex math into a single figure, which keeps communication among leadership clean.

• Scale-agnostic evaluation: It can be applied regardless of an investment's size, making it easy to compare options side by side.

Where IRR Falls Short

• It ignores investment scale: IRR alone can't tell you the absolute dollar value an investment creates.

• It can go wrong with complex cash flows: When cash-flow patterns get complicated, IRR can be hard to compute — and you can even end up with multiple IRRs.

• Limited as a risk gauge: A high IRR signals high returns, but it can just as easily signal high risk.

Why You Should Use IRR and NPV Together

IRR is great for building an intuitive read on an investment's profitability, but when it's time to actually pull the trigger, you'll make a sharper call by pairing it with NPV. NPV shows the absolute value an investment adds, filling in the investment scale and cash-flow patterns that IRR alone tends to miss.