NPV Calculator
By Jan Suski. I go deep on every review, checking every number against its source and digging up details other coverage misses, a habit from six years of SEO and link building for tech companies. Bylines at Surfer, Brand24, and Senuto. How the scoring works.
How it works
Enter what a project costs upfront, the cash flow you expect back each year, how many years it runs, and a discount rate. The calculator discounts every future cash flow back to today's dollars, sums them, and subtracts the initial investment, then reports net present value, internal rate of return, and a payback period. Every field recalculates the moment you type.
Who it's for
Built for small business owners weighing a capital purchase, corporate finance analysts screening projects against the same required return, and buyers of any SaaS platform sizing up if a subscription pays for itself, the same question the SEO ROI calculator answers for marketing spend specifically. The discount rate you enter carries the whole risk judgment; the calculator won't set it for you.
Reading the results
A positive NPV means the project's discounted cash flows exceed the initial investment at your chosen rate. A negative NPV means they fall short, and IRR shows the exact rate where the two break even. Raise the discount rate and NPV falls; a project clearing its hurdle rate at 10% can turn negative once that rate climbs past its own IRR.
When to use it
- Deciding if a project or purchase clears your company's required rate of return.
- Comparing two projects of different sizes on the same discounted basis.
- Checking if a SaaS subscription's cost savings justify the price before renewal.
- Working out the highest price you could pay and still hit your target return, or the exact rate a project needs to break even.
Net present value
$0
Internal rate of return
0%
Payback period
0 years
Discount rate sensitivity
| Discount rate | Net present value |
|---|---|
| % | $0 |
| % | $0 |
| % | $0 |
The formula
NPV (level cash flow) = −Investment + Cash flow × [1 − (1 + rate)−n] ÷ rate
IRR = the rate where NPV equals zero, found by testing rates between −99% and 1,000% until the result narrows to zero
Payback period = Investment ÷ Annual cash flow (undiscounted)
A positive NPV means the project clears your discount rate. IRR solves the same equation for the rate. NPV solves it for the dollar value.
The calculator assumes one identical cash flow every year. A project with uneven year-to-year cash flows, a delayed first payment, or a residual sale value at the end won't match this output exactly, and needs a full multi-row NPV model instead.
How this is calculatedformula, sourced definitions
Net present value discounts every future cash flow back to today's dollars, then subtracts what the project costs upfront. Corporate finance textbooks and the CFA Institute's curriculum define the formula the same way: NPV = −Investment + Σ [Cash flow ÷ (1 + rate)^t], summed across every period t from 1 to n.
For a level annual cash flow, the same amount every year, that summation collapses into a single annuity formula: NPV = −Investment + Cash flow × [1 − (1 + rate)−n] ÷ rate. The calculator runs this version directly, since it takes one cash-flow figure and repeats it across every year you enter.
Internal rate of return is the discount rate that makes NPV land at zero. There's no algebraic formula for it once more than two periods are involved, so the calculator tests rates between −99% and 1,000% with a bisection search, narrowing the range until the result sits within a fraction of a cent of zero.
Worked example$50,000 investment, $15,000 a year, 5 years, 10% discount rate
A $50,000 equipment purchase returns $15,000 a year for 5 years. At a 10% discount rate, those five payments are worth $56,861.80 today, not $75,000. Subtract the $50,000 cost and NPV comes out to $6,861.80. The project clears its hurdle rate.
Run the same cash flows through the calculator's IRR search and it converges on 15.24%, the exact rate at which this project's NPV hits zero. Payback period, ignoring the time value of money entirely, comes to 3.33 years. That's $50,000 divided by $15,000 a year.
Raise the discount rate to 13%, roughly what a higher-risk venture might require, and NPV falls to $2,758.47, still positive. Drop it to 7% and NPV climbs to $11,502.96. Both numbers match the sensitivity table above at those two rates.
What this does and doesn't tell youlevel cash flows, discount rate choice, risk
This calculator assumes the same cash flow every year, which rarely matches a real project exactly. A renovation that saves money slowly in year one and fully by year three, or equipment sold for salvage value at the end of its life, needs a spreadsheet model with a separate cash flow entered for every period.
The discount rate carries the entire risk judgment, and the calculator doesn't set it for you. A common starting point is a company's weighted average cost of capital (WACC), adjusted upward for projects carrying more risk than the business normally takes on. Getting that single number wrong skews every result that follows it.
NPV also says nothing about how the investment gets funded, and it ignores taxes and inflation unless you've already built them into the cash flow and rate you entered. Check a platform's actual published pricing before plugging in a cash-flow estimate you haven't verified.
What does a negative NPV mean?
The project's discounted cash flows don't cover the upfront cost at your chosen rate. A $50,000 investment returning $15,000 a year for 5 years turns negative once the discount rate passes 15.24%, the project's IRR, since a higher rate discounts each future payment down further.
What discount rate should I use?
For a business decision, start with your company's weighted average cost of capital, then add a few percentage points for a project riskier than the business's normal operations. For a personal decision, your discount rate is whatever return you'd earn on the next-best use of that money.
Can this calculator handle uneven cash flows?
No. It runs the level-annuity version of the NPV formula, which assumes one identical payment every year. A project with a different amount each year, or a lump sum at the end, needs a row-by-row spreadsheet model that discounts each period on its own. The CAGR calculator handles a related but different case: a single lump-sum investment with one payout at the end, no repeating annual cash flow.
How is NPV different from IRR?
NPV reports a dollar amount at a discount rate you choose. IRR reports the discount rate itself, the exact rate at which NPV would equal zero. The calculator above computes both from the same four inputs, so neither needs solving by hand.
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