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NPV and IRR calculator

Calculate net present value, internal rate of return, payback period and profitability index from a list of periodic cash flows.

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NPV and IRR calculator
Paste a list of periodic cash flows, one amount per line, and this tool calculates net present value (NPV), internal rate of return (IRR), the payback period, the discounted payback period and the profitability index — all at once, with a full breakdown by period underneath. It is built for anyone evaluating a project, an investment or a purchase: does this initial outlay pay off, and how does it compare with an alternative that discounts value differently?
The discount rate sets how future cash flows are brought back to today's value, and the period length (year, quarter or month) decides what each line represents and how the payback figures are expressed. With "Enter initial investment separately" off, the first line of the pasted list is treated as period 0 — usually a negative number for the initial outlay; turn it on to keep that amount in its own field instead and paste only the inflow periods. Turn on Modified IRR to add an MIRR figure using a separate reinvestment rate for positive cash flows, alongside the ordinary IRR. The sensitivity table recomputes NPV at a handful of other discount rates you list, so you can see at a glance how sensitive the result is to that assumption.
Lines can use a leading minus sign or accounting-style parentheses for an outflow, and currency symbols or thousands separators are ignored when a number is parsed — "$-1,000" and "(1000)" both read as −1000. A line that isn't a recognizable amount is skipped and counted separately rather than breaking the whole calculation. Output format switches between a labeled report and a comma-separated table that pastes cleanly into a spreadsheet.
Everything runs locally in your browser — cash flows, rates and results are never uploaded anywhere. When you are done, copy the result, download it as a .txt file, or send it to the input of another tool to keep working with the numbers.
FAQ
How is IRR calculated?
The tool searches for the discount rate at which NPV equals zero, using a bracketed bisection search. It exists only when the cash flow series has at least one sign change — an all-positive or all-negative series has no IRR.
What is the difference between payback and discounted payback period?
Payback period is the point where the raw, undiscounted cash flows recover the initial investment. Discounted payback period does the same using cash flows discounted at your chosen rate, so it is always equal to or later than the plain payback period.
What does the profitability index mean?
It is the present value of every cash flow after period 0, divided by the size of the period-0 outflow. A value above 1 means the project creates value at the given discount rate; below 1 means it destroys value.
Can I paste inflows only and enter the investment separately?
Yes. Turn on "Enter initial investment separately" and use the Initial investment field for the up-front outlay — the pasted list then holds only the cash flows for periods 1 onward.
Is my financial data uploaded anywhere?
No. Every calculation runs entirely in your browser — cash flows, rates and results never leave your device.