NPV / IRR Calculator

Analyze Net Present Value (NPV), calculate Internal Rate of Return (IRR / MIRR), map project profitability indexes, and view real inflation-adjusted curves.

Analysis settings

Discount Rate (%)

Financing Rate (%)

Reinvest Rate (%)

Inflation Rate (%)

Investment Periodic Cash Flows

Enter one cash flow amount per line. Period 0 represents initial capital (usually negative). Subsequent rows denote periodic gains or losses.

Cumulative Payback / Break-Even Curve

Project Outcomes

Nominal NPV:$16,120

Inflation-Adjusted NPV:$8,936

IRR (Newton-Raphson):16.62%

Modified IRR (MIRR):13.34%

Profitability Index (PI):1.16

Payback Period:2.86 periods

Discounted PV Details

Period	Discounted PV
Period 0	-$100,000
Period 1	$27,273
Period 2	$33,058
Period 3	$26,296
Period 4	$17,075
Period 5	$12,418

PI Metrics: A Profitability Index greater than 1.0 indicates that the present value of future capital inflows exceeds the initial investment outlay.

Capital budgeting metrics: NPV, IRR, and MIRR

Net Present Value (NPV) discounts future cash flow elements to estimate present value margins. The index maps: NPV = Σ [CF_t / (1+r)^t].

Modified IRR (MIRR) resolves standard IRR pitfalls by assuming capital is financed at borrow rates and reinvested at reinvestment rate indexes.

Built and maintained by Meet Shah · Last updated 4 August 2026

What this tool is used for

Discounting a series of cash flows to a present value.
Finding the rate at which a project's net present value reaches zero.
Comparing two investments with different cash-flow timing.
Testing how sensitive a decision is to the discount rate.
Producing figures for an investment appraisal.

Frequently Asked Questions

What does net present value tell me?: What a future cash flow stream is worth in today's money, after discounting each period by the rate you could otherwise earn. A positive NPV means the project beats that alternative; a negative one means the money is better deployed elsewhere, whatever the headline profit looks like.
What is IRR and why is it found by iteration?: The discount rate at which NPV equals zero. There is no closed-form solution for an arbitrary cash flow series — it is a polynomial root — so it has to be found numerically, here by bisecting a bracketing interval until NPV crosses zero.
Can a project have more than one IRR?: Yes, whenever the sign of the cash flows changes more than once — Descartes' rule of signs allows one root per sign change. A project with a large cleanup cost at the end can have two mathematically valid IRRs, which is the clearest argument for judging by NPV instead.
What does MIRR fix?: IRR implicitly assumes interim cash flows are reinvested at the IRR itself, which is usually optimistic. MIRR lets you state a realistic reinvestment rate separately, so a project showing a spectacular 40% IRR often comes back to something believable once the assumption is made explicit.
What discount rate should I use?: Your cost of capital — the return available on the next-best use of the money at similar risk. It is the input that swings the answer most, so the useful practice is to compute NPV across a range and see at what rate the decision flips, rather than defending one number.

Common errors and gotchas

Reading IRR as a return you will actually earn, which assumes reinvestment at the same rate.
Getting multiple IRRs from a cash flow that changes sign more than once, where the measure breaks down.
Using a discount rate that does not reflect the project's risk.
Putting the initial outlay in the wrong period, which shifts everything.
Comparing IRRs across projects of very different size or duration.