What is Net Present Value?
Net Present Value (NPV) is the difference between the present value of future cash inflows and the cost of an investment, discounted at your required rate of return. It answers a fundamental question: in today's dollars, does this investment create or destroy value?
A positive NPV means the investment is expected to generate more value than it costs — it exceeds your required return. A negative NPV means the opposite. NPV is considered the gold standard in capital budgeting because it directly measures value creation in dollar terms.
How is NPV calculated?
NPV sums all future cash flows, each discounted back to today's dollars at your chosen rate r:
NPV = CF₀ + CF₁(1+r) + CF₂(1+r)² + … + CFₙ(1+r)ⁿ
CF₀ is typically the initial investment (a negative number). Each future cash flow is divided by (1+r) raised to the power of its year, which shrinks it to reflect how much less a future dollar is worth compared to a dollar today.
Worked example: You're considering a $50,000 investment that returns $20,000/year for 3 years. Your required return (discount rate) is 10%. NPV = −50,000 + 20,0001.1 + 20,0001.21 + 20,0001.331 = −50,000 + 18,182 + 16,529 + 15,026 = −$263. The NPV is just barely negative — at a 10% hurdle rate, this investment doesn't quite pay. Drop the discount rate to 9% and it turns positive.
When to use NPV
NPV is the right tool when you need to know how much value an investment actually creates:
- Comparing mutually exclusive projects: If you can only build one of two factories, pick the one with the higher NPV — it creates more absolute value regardless of which has the higher IRR.
- Go / no-go decisions: Any project with a positive NPV clears your hurdle rate and should theoretically be pursued. A negative NPV destroys value relative to your alternative.
- Valuing a business or asset: Discounted Cash Flow (DCF) valuation is just NPV applied to all future free cash flows of a company. The intrinsic value of any asset is the NPV of what it will generate.
Common mistakes
- Using the wrong discount rate: The discount rate should match the risk of the cash flows. Using a company's average cost of capital for a high-risk venture will overstate NPV. Higher risk requires a higher discount rate.
- Inconsistent cash flow timing: This calculator assumes annual cash flows. Mixing monthly and annual figures without converting will produce incorrect results.
- Treating NPV = 0 as a failure: An NPV of exactly zero means the investment earns precisely your required return — not a bad outcome. It's only a failure if your hurdle rate already includes a profit margin above your cost of capital.
- Ignoring terminal value: For long-lived assets, explicitly modeling cash flows year-by-year for 30 years is unwieldy. A common approach is to model 5–10 years explicitly, then add a terminal value (the present value of all cash flows beyond that horizon) as a final lump sum in the last year.
How to use this calculator
Enter your discount rate (required rate of return), your initial investment as Year 0, and then add expected cash flows for each future year. The calculator returns the total NPV — positive means the investment clears your hurdle, negative means it doesn't.
Frequently Asked Questions
What discount rate should I use?
The discount rate should reflect the opportunity cost of your capital — the return you could earn on an investment of similar risk. For corporate projects, this is often the Weighted Average Cost of Capital (WACC). For personal investments, use your expected return from an alternative (e.g., 7–10% for a stock market alternative). Higher risk projects warrant higher discount rates.
What does a positive NPV mean?
A positive NPV means the investment is expected to generate more value than your required return, in today's dollars. For example, an NPV of $5,000 means you'd expect to be $5,000 richer (in present value terms) by taking this investment rather than the alternative represented by your discount rate.
When should I use NPV vs IRR?
Use NPV when comparing mutually exclusive projects or when you want to know the absolute dollar value created. Use the IRR calculator when you want a quick percentage return to compare against a hurdle rate. When they conflict, NPV is generally more reliable — IRR can be misleading when project sizes differ or when cash flows change sign multiple times.
How does compounding frequency affect NPV?
This calculator uses annual discounting. If your cash flows are monthly, convert your annual discount rate to a monthly rate (divide by 12 for an approximation, or use (1 + r)112 − 1 for exactness) and treat each month as a period.