NPV and IRR Calculator
Enter a list of cash flows to get net present value, every internal rate of return, MIRR, payback and discounted payback, with an NPV profile chart.
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About this toolWhat is the NPV and IRR Calculator?
The NPV and IRR Calculator evaluates any project or investment described as a series of cash flows: money out (negative) and money in (positive), one value per period, starting with period 0. It reports net present value at your discount rate, the internal rate of return, the modified internal rate of return (MIRR), the simple and discounted payback periods and the profitability index.
The IRR solver scans the whole range from -99% to 10,000% and finds every rate where NPV is zero, so it reports two IRRs when unusual cash flows produce two, and says clearly when there is none instead of returning a misleading number. An NPV profile chart plots NPV against the discount rate, and a table lists each flow with its present value and running totals.
Periods can be years, quarters or months. Annual rates are converted to the matching per-period rate, and IRR is shown both per period and annualized.
- NPV with period 0 undiscounted, as in finance textbooks
- Every IRR found by grid scan plus safeguarded Newton and bisection
- Clear messages for no IRR and multiple IRRs
- MIRR with separate finance and reinvestment rates
- Simple and discounted payback, profitability index
- NPV profile chart and a table of discounted and cumulative flows
How to use the NPV and IRR Calculator
- Type the cash flows one per line, starting with the period 0 amount (usually the negative investment). Commas, semicolons and brackets for negatives also work.
- Enter the discount rate, which is your required return or cost of capital, and choose whether each period is a year, a quarter or a month.
- Optionally set separate finance and reinvestment rates for MIRR; blank uses the discount rate.
- Read NPV, IRR, MIRR, payback, discounted payback and the profitability index, and any note about multiple or missing IRRs.
- Use the NPV profile chart and the cash flow table to see how sensitive the decision is to the rate.
Worked examples
A five-year project
Input
-50,000; 12,000; 15,000; 18,000; 20,000; 9,000 at 8%
Output
NPV 9,086.02; IRR 14.60%; MIRR 11.67%; payback 3.25 years; discounted payback 3.80 years
NPV is positive at 8%, so the project clears the hurdle. MIRR is lower than IRR because it assumes cash received is reinvested at 8%, not at 14.6%.
Two IRRs
Input
-100; 230; -132
Output
IRRs 10.00% and 20.00%
The flows change sign twice, so NPV crosses zero twice. NPV is positive only between 10% and 20%, and slightly negative at 8%. A single-answer IRR function would return whichever root it reached first.
No IRR at all
Input
-1,000,000; 300,000 for four years; -400,000 closing cost
Output
IRR none; NPV at 10% -297,408.90; MIRR at 10% 4.17%
NPV is negative at every rate, so no IRR exists. The calculator says so and the MIRR and NPV still give a usable answer.
Monthly cash flows
Input
-12,000 then 600 a month for 24 months, periods in months, 10% a year
Output
IRR 1.51% a month (19.75% a year); NPV 1,058.74
The 10% annual rate becomes 0.797% a month. IRR per month is compounded up to an annual figure so it can be compared with yearly returns.
Background and insight
Net present value discounts every cash flow back to period 0 at the discount rate r and adds them: NPV = Σ CFₜ ÷ (1 + r)ᵗ. A positive NPV means the project returns more than r after paying back the investment, in present-day money. Note that the NPV function in Excel and Google Sheets discounts its first argument by one period, so the period 0 investment must be added outside it. This calculator does not discount period 0, which matches the textbook definition.
The internal rate of return is the discount rate that makes NPV exactly zero. There is no closed formula, so it has to be found numerically. Simple solvers start from a guess and apply Newton's method, which can wander off or converge to only one of several answers. This tool first evaluates NPV across a fine grid of rates to find every interval where it changes sign, then narrows each one with Newton steps that fall back to bisection whenever a step would leave the interval. Descartes' rule of signs says the number of IRRs is at most the number of sign changes in the cash flows, which is why mining, nuclear and other projects with closing costs can have two.
MIRR fixes two weaknesses of IRR. It discounts the outflows at a finance rate and compounds the inflows to the final period at a reinvestment rate, then finds the single rate that links the two: MIRR = (FV of inflows ÷ PV of outflows)^(1/n) − 1. It always has exactly one answer, and it does not assume interim cash is reinvested at the IRR itself. Payback period counts how long until cumulative cash flow turns positive; discounted payback does the same with present values, and both interpolate within the period.
Common use cases
Capital budgeting
Decide whether equipment, a new product line or an expansion earns more than the cost of capital.
Comparing projects
Rank mutually exclusive options by NPV and see on the profile chart where their ranking would flip.
Real estate and private deals
Evaluate a property or private investment from its purchase, yearly net income and sale proceeds.
Corporate finance coursework
Check NPV, IRR, MIRR and payback answers, including the tricky multiple-IRR textbook cases.
Tips and limitations
- When NPV and IRR disagree on which of two projects is better, prefer NPV: it measures value created in money, while IRR ignores scale.
- Cash flows must be evenly spaced. For irregular dates, use the Investment Returns Calculator, which computes XIRR.
- Payback ignores everything after the break-even point, so use it as a liquidity check, not as the decision rule.
- If there are several IRRs, none of them is a reliable hurdle comparison. Use NPV at your rate or MIRR.
- Use after-tax cash flows and a discount rate that matches their risk; a riskier project deserves a higher rate.
Frequently asked questions
How do you calculate NPV?
Discount each cash flow by (1 + r) raised to its period number and add them up, with the period 0 flow undiscounted. For -50,000 followed by 12,000, 15,000, 18,000, 20,000 and 9,000 at 8%, NPV is 9,086.02.
What does a positive NPV mean?
It means the project returns more than the discount rate and adds that much value in present-day money. Zero means it earns exactly the discount rate, and negative means you would be better off with the alternative that earns the discount rate.
Why can a project have more than one IRR?
When cash flows change sign more than once, such as an investment followed by income and then a large closing cost, the NPV curve can cross zero more than once. Each crossing is a valid IRR. The calculator lists all of them and recommends NPV or MIRR for the decision.
Why does my NPV differ from Excel's NPV function?
Excel's NPV discounts the first value it is given by one full period. If you include the period 0 investment inside NPV(), it gets discounted when it should not be. Use =NPV(rate, flows from period 1) + period 0 flow to match this calculator.
What is the difference between IRR and MIRR?
IRR assumes interim cash flows are reinvested at the IRR itself and can have zero or several answers. MIRR uses explicit finance and reinvestment rates and always gives exactly one answer, which is usually closer to what the project really earns.
What is discounted payback period?
The time until the cumulative present value of the cash flows turns positive. It is always longer than simple payback because later cash flows are worth less, and if NPV is negative the project never pays back on a discounted basis.
Can I use monthly or quarterly cash flows?
Yes. Set each period to months or quarters. The annual discount rate is converted to the equivalent per-period rate, and the IRR is shown per period and as an annual rate.
Is there an in-depth guide to the NPV and IRR Calculator?
Yes. “Time Value of Money: PV, FV, NPV, IRR, CAGR and ROI Explained” covers the background, how it works, common pitfalls and worked examples. Read the full guide.
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