What Is Net Present Value (NPV)?

Net Present Value (NPV) is the most widely used method for evaluating the financial viability of an investment or project. It calculates the difference between the present value of all future cash inflows generated by an investment and the initial cost of that investment. A positive NPV means the project creates more value than it costs; a negative NPV means it destroys value.

NPV is superior to simpler metrics like payback period or accounting rate of return because it accounts for the time value of money — recognizing that $1 received today is worth more than $1 received in the future. By discounting all cash flows to today's dollars using the required rate of return (discount rate), NPV provides a true measure of value creation in today's terms.

The NPV Formula

NPV = −C₀ + CF₁/(1+r)¹ + CF₂/(1+r)² + ... + CFₙ/(1+r)ⁿ. Where C₀ = initial investment, CFₜ = cash flow in period t, r = discount rate (required rate of return), n = project life in years. The formula sums the present value of each year's cash flow and subtracts the upfront cost.

How to Interpret NPV

NPV > 0: The project earns more than the required rate of return. Accept the project — it creates shareholder value. NPV = 0: The project earns exactly the required return. Accept or reject based on strategic considerations. NPV < 0: The project fails to meet the required return. Reject the project — you'd earn more by investing elsewhere at the discount rate.

NPV vs IRR: When to Use Each

While both NPV and IRR are DCF methods, NPV is generally superior for decision-making. IRR can give misleading results for projects with non-conventional cash flows (multiple sign changes), mutually exclusive projects of different scales, or projects with very different time horizons. NPV always gives the correct accept/reject decision when the discount rate represents the true opportunity cost. IRR is best used as a secondary metric to understand the project's inherent return rate.

Choosing the Right Discount Rate

The discount rate is the most critical — and most debated — input in NPV analysis. For corporate projects, the standard choice is WACC (Weighted Average Cost of Capital), which blends the cost of debt and equity weighted by their proportions in the capital structure. For higher-risk projects, a risk premium is added. Personal investors often use their expected portfolio return (e.g., 7–10% for stock market returns) as the hurdle rate. The discount rate should always reflect the risk of the specific project, not the company's average risk.