NPV Calculator

How NPV Calculator Works

Each future year's cash flow is discounted back to today's value using your chosen discount rate — money received further in the future is worth less today, since it could otherwise have been earning that same rate of return in the meantime. Adding up all the discounted cash flows and subtracting the initial investment gives the NPV.

Who Uses NPV Calculator and Why

• Evaluating whether a business investment or project is worth pursuing based on its initial cost and a projected series of future cash flows.
• Comparing two competing investment opportunities with different upfront costs and future cash flow patterns on equal footing.
• Testing how sensitive an investment decision is to the assumed discount rate by re-running the calculation at a higher or lower rate.
• Checking whether a project's expected returns actually beat what the same money could earn elsewhere at a comparable risk level.

Mistakes to Avoid

• Choosing a discount rate that doesn't reflect the actual required rate of return or cost of capital for the decision — since a higher discount rate lowers NPV and a lower one raises it, an unrealistic rate can flip a marginal investment from apparently good to apparently bad or vice versa.
• Entering cash flows out of order or with the wrong sign — the initial investment is a separate upfront cost input, while the cash flow list should represent the returns received in each subsequent year, starting with year 1.
• Treating a positive NPV as a guarantee of a good outcome rather than an estimate — NPV is only as reliable as the projected cash flows and discount rate fed into it, both of which involve real-world uncertainty.

Tips for Best Results

• Re-run the calculation at a couple of different discount rates to see how sensitive the NPV conclusion is — an investment that looks attractive at one reasonable rate but turns negative at a slightly higher one is a much closer call than one that stays positive across a range of rates.
• Use a discount rate that reflects what the money could otherwise earn at a similar risk level, not an arbitrary round number, for the most meaningful comparison.

Fixing Common Problems

My NPV came out negative even though the total cash flows add up to more than the initial investment. — This is expected when the discount rate is high enough or the cash flows are spread far enough into the future — discounting reduces the value of later cash flows, so a project can have cash flows that sum to more than the investment in raw dollars while still having a negative NPV once discounted.

Terms Explained

NPV (Net Present Value): The sum of all future cash flows discounted back to today's value, minus the initial investment — positive NPV suggests the investment is expected to be worth more than its cost at the chosen discount rate.

Discount rate: The rate used to discount future cash flows back to present value, typically reflecting the required rate of return or cost of capital for the decision.