NPV vs IRR: Which to Use and When
By Devon Coombs, CPA, MBA · Teaching Professor of Finance, Santa Clara University · Reviewed August 2026
Use NPV to decide whether a deal creates value and to choose between competing deals, because NPV measures the dollars of wealth added at your required return. Use IRR to communicate an annualized return and to test a deal against a hurdle rate. When the two disagree on a ranking, NPV is generally the safer guide, since IRR embeds scale and reinvestment assumptions that can distort comparisons.
| NPV | IRR | |
|---|---|---|
| What it measures | Dollars of value created above the required return | The annualized rate that sets NPV to zero |
| Units | Present-value dollars | Percent per year |
| Reinvestment assumption | Interim cash flows reinvest at the discount rate | Interim cash flows reinvest at the IRR itself |
| Scale | Rewards larger value creation directly | Ignores size; a small deal can post a high IRR |
| Ranking mutually exclusive deals | Orders deals by wealth added | Can favor a smaller or shorter deal over a more valuable one |
| Failure modes | Requires a defensible discount rate | Can have multiple or no solutions when cash flows change sign more than once |
When NPV is the right tool
NPV is the right tool whenever the question is whether to commit capital, and especially when choosing among mutually exclusive alternatives such as two business plans for the same site. Because it discounts at your required return, it prices risk explicitly and rewards scale, so a larger deal that adds more dollars of wealth wins even when its percentage return is lower. In practice the discount rate deserves as much scrutiny as the cash flows, since NPV is only as defensible as the rate behind it.
When IRR is the right tool
IRR works well as a screening and communication device, since investors, promote structures, and track records are quoted in percentage terms. It is most reliable for a single conventional deal, one outflow followed by inflows, measured against a clearly stated hurdle. It tends to break down when cash flows change sign more than once or when deals differ in size or duration, and a high IRR on a short hold often overstates what capital can earn over a full investment horizon.
The common mistake
The common error is ranking competing deals by IRR and assuming the ordering matches value creation. A deal that returns capital quickly can post a spectacular IRR while adding fewer dollars of wealth than a larger or longer alternative, because IRR silently assumes every interim dollar keeps compounding at that same high rate. An investor who selects the 25 percent IRR deal over the 18 percent alternative may be choosing less value and a heavier reinvestment burden. Computing NPV at a realistic required return typically settles the ranking.
Work the numbers yourself
Both concepts are taught in depth, with practice questions, in the free Real Estate Finance course.