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Checked August 16, 2026
What NPV & IRR Calculator does, with a checked example
An investment cash-flow series becomes two answers here: its value today at a selected per-period discount rate, and the break-even rate that makes that value zero. Record outlays as negative cash flows and receipts as positive amounts. Timeline diagrams show when each amount occurs and help compare projects side by side. The usual source of a surprising result is mismatched periods. If cash flows are monthly, the discount rate must also be monthly; an annual percentage cannot be used unchanged.
Worked example
A concrete input and expected output from the current implementation.
Input
Discount rate per period: 5%
Cash flows: period 0 = -1000; period 1 = 1100
->
Expected output
NPV: 47.62
IRR: 10.00%
At 5 percent, -1000 + 1100 / 1.05 = 47.6190476, which rounds to 47.62. Solving -1000 + 1100 / (1 + r) = 0 gives r = 0.10, so the IRR is 10 percent.