NPV vs IRR: What's the Difference and When to Use Each

Key takeaway

NPV and IRR both come from discounted cash flow but express value differently. What each measures, why they sometimes disagree, and which one to trust.

Net present value (NPV) and internal rate of return (IRR) are the two most common ways to judge whether an investment is worth making. They use the same discounted-cash-flow machinery but express the answer differently — NPV as an amount of value created, IRR as a percentage return — and they occasionally disagree. Knowing which to trust, and when, is core to any valuation or capital-budgeting decision.

What NPV is

Net present value discounts every future cash flow back to today at a chosen rate (usually WACC) and sums them, minus the upfront investment: NPV = Σ CFₜ ÷ (1 + r)ᵗ − initial outlay. A positive NPV means the investment creates value above the required return; a negative NPV means it destroys value. NPV answers 'how much value does this create, in today's money?'

What IRR is

The internal rate of return is the discount rate at which NPV equals zero — the project's own break-even return. If the IRR exceeds your required return (the hurdle rate or WACC), the investment is attractive. IRR answers 'what return does this earn?', which is intuitive and why investors quote it, but it hides the scale of the return.

Why they usually agree

For a conventional investment — cash out first, cash in later — NPV and IRR give the same accept-or-reject signal: if IRR is above the discount rate, NPV is positive. Most of the time either metric points the same way.

Why they sometimes disagree

Two situations break the tie. First, scale: a small project can have a high IRR but a small NPV, while a large project has a lower IRR but far more NPV — and value created is what actually makes you richer. Second, unconventional cash flows (outflows in later years) can produce multiple IRRs, or none, making IRR meaningless. When they conflict, trust NPV.

A worked example

Project A costs $100k and returns $130k in a year: NPV at 10% is $130k ÷ 1.1 − $100k = $18.2k, IRR is 30%. Project B costs $1m and returns $1.2m in a year: NPV at 10% is $1.2m ÷ 1.1 − $1m = $90.9k, IRR is 20%. A has the higher IRR (30% vs 20%) but B creates five times the value. If you can only pick one and capital allows, NPV says take B.

Which to use

Use NPV to decide how much value a decision creates and to choose between mutually exclusive projects. Use IRR to communicate return and compare against a hurdle, but never let a high IRR on a tiny project override a larger NPV. Sophisticated investors look at both, plus payback and sensitivity.

Compute both automatically

A worked NPV and IRR example

Invest $1,000 today and receive $400 in each of the next four years. At a 10% discount rate the present values sum to about $1,268, so NPV ≈ $268 — the project adds value. The IRR is the rate that makes NPV zero, here roughly 22%. Because 22% comfortably exceeds a 10% hurdle rate, both rules agree: accept the project.

The rules diverge on scale. A small project with a 40% IRR but $50 NPV creates less value than a large one with a 15% IRR and $2m NPV. When ranking mutually exclusive options, follow NPV — it measures dollars of value created, which is what maximises wealth.

Watch for multiple IRRs

When cash flows change sign more than once — an outflow, inflows, then a large decommissioning outflow — a project can have several IRRs, none meaningful. NPV has no such ambiguity, another reason it is the primary decision rule.

EasyFinancialModels computes NPV, IRR and equity IRR inside every model, discounting your unlevered free cash flows at WACC and solving for IRR with a Newton-Raphson routine. Build a DCF valuation model free for up to 3 years and read NPV and IRR straight off the linked output.

Using both in practice

In a real appraisal, compute NPV to decide whether a project creates value and to rank competing uses of capital, then quote IRR alongside it to communicate the return in a single, intuitive percentage. Where the two rules conflict, trust NPV — but understand why they diverge, because the reason, whether scale, timing or unconventional cash flows, is itself useful information about the investment.

Frequently asked questions

What is the difference between NPV and IRR?

NPV is the dollar value created by an investment at a chosen discount rate. IRR is the discount rate at which NPV equals zero — the percentage return implied by the cash flows.

When can NPV and IRR disagree?

On mutually exclusive projects of different scale or timing, or with non-conventional cash flows. NPV is the more reliable rule because it measures absolute value created.

Which should I use?

Use NPV to decide whether a project adds value and to rank mutually exclusive options; use IRR to communicate return versus a hurdle rate. Best practice reports both.

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More DCF & Valuation guides

How to Build a DCF Model in Excel (Step-by-Step Guide) · Hurdle Rate Explained: How to Set the Minimum Return (and Use It with NPV & IRR) · DCF Valuation Explained for Founders and Analysts · How to Calculate WACC and Cost of Equity (CAPM Formula) · How to Calculate Terminal Value in a DCF (Gordon Growth & Exit Multiple)

About the author

Every model is built and reviewed by the project's Financial Advisor — a Fellow Chartered Accountant (FCA) of the Institute of Chartered Accountants of Pakistan (ICAP), Chartered Global Management Accountant (CGMA) and Associate Chartered Management Accountant (ACMA) with around two decades of corporate finance, audit and accounting experience, designing investor-grade financial models across industries. Full credentials and background are available on LinkedIn. More about the author →

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