THE NUMORIX GUIDE
How to use the NPV Calculator
Last reviewed September 14, 2026
What this calculator does
The engine converts the annual discount rate to a periodic rate, r = discount rate / 100 / periods per year.
Formula and method
The engine converts the annual discount rate to a periodic rate, r = discount rate / 100 / periods per year. For end timing it discounts cash flow i by (1 + r)^(i + 1); for beginning timing the first cash flow has exponent 0. It adds all discounted nonnegative flows and the discounted negative flows to -initialInvestment at time zero.
Variables and inputs
Enter a nonnegative initial investment, comma-separated signed future cash flows, an annual discount rate in percent, periods per year, and end- or beginning-of-period timing. Positive entries are inflows and negative entries are outflows after time zero.
Worked example
For a $1,000 initial investment and three end-of-year inflows of $600 at a 10% annual rate, NPV = -1,000 + 600/1.10 + 600/1.10^2 + 600/1.10^3 = $492.11. The discounted inflows total $1,492.11 and the undiscounted net cash flow is $800.
How to interpret the result
A positive NPV means the entered future cash flows exceed the time-zero investment after discounting at the chosen rate. It is a comparison against one required-return assumption, not a standalone investment recommendation or a probability of profit.
Common mistakes to avoid
Use the cash-flow signs to show direction instead of entering every amount as positive. Match periods per year to the rate and timing convention. Do not discount the initial investment again; the engine treats it as a time-zero outflow.
Assumptions and limitations
The route assumes a constant discount rate and exact regular periods. It does not infer taxes, fees, salvage value, inflation, working capital, risk, or financing effects unless they are included in the cash-flow list. It also does not solve for IRR, and beginning timing changes the first discount exponent rather than the displayed schedule label.