Only meaningful against your cost of capital and the risk taken. A corporate project might need 12% to 15%; real estate deals are often underwritten to 15% to 20%; venture funds target 25% or more to compensate for the losses. An IRR below your cost of capital destroys value however large it looks in isolation.

Why does my IRR seem too high?

Usually the reinvestment assumption. IRR credits you with redeploying every distribution at the IRR itself, which is unrealistic at high rates. Compute MIRR with a reinvestment rate you could actually achieve — the difference is often several points, and occasionally more than ten.

What is the difference between IRR and ROI?

ROI is total profit over total invested and ignores time completely. IRR is annualised and accounts for exactly when each cash flow occurred. The worked example above returns 55% of the original outlay over five years, which is a 14.4% IRR precisely because most of it arrives before year five. The same 55% paid entirely in year five would be about 9.2%. ROI cannot tell those apart and IRR can.

Yes. If you receive back less than you put in, the IRR is negative and quantifies the annual rate of loss. Below −100% it becomes meaningless, which is why solvers clamp there.

Why does the calculator sometimes say "no solution"?

Either no rate makes the NPV zero for those cash flows, or the solver failed to converge. Both are real answers. The alternative — returning whatever value the iteration happened to be holding — would present a failure as a result, which is worse than saying so.

Should I use IRR or NPV to decide?

NPV to decide, IRR to rank and communicate. NPV is unique, stated in money, and correctly accounts for project size. IRR is intuitive and comparable but blind to scale and dependent on its reinvestment assumption. Where they disagree, NPV is the one to follow.

IRR Calculator

Internal Rate of Return is the discount rate that makes the NPV of a cashflow stream equal zero — the standard metric for comparing investments with uneven cash flows.

Annual cash flows

Year 0 should be negative (your investment). Following years are returns. Add as many as needed.

Year 0

Year 1

Year 2

Year 3

Year 4

Year 5

Discount and reinvestment

Discount rate % (your cost of capital)

Reinvestment rate % (for MIRR)

What you can actually redeploy distributions at. IRR silently assumes this equals the IRR itself.

Internal rate of return (IRR)

14.41%

Annualised — comparable to interest rates

Modified IRR (MIRR)

12.03%

Reinvesting distributions at 8% rather than at the IRR

Net present value at 8%

$20,119

Positive — clears your cost of capital

Total inflows

$155,000

Total outflows

-$100,000

Net gain

$55,000

Undiscounted — ignores timing entirely

IRR is 2.38% higher than MIRR here. That gap is the reinvestment assumption: IRR credits you with redeploying every distribution at 14.41%, while MIRR only assumes 8%. The wider the gap, the more the headline IRR is flattering the deal.

Use IRR for: private equity, real estate deals, multi-year business projects — anything where timing matters and the cash flow pattern is uneven. Use NPV to decide whether to proceed, and IRR to rank alternatives.

Analysis & insights

Your total in is $155,000, based on the inputs above. Tax outcomes drive the math behind nearly every other financial decision — savings rate, affordability, retirement.

Quick estimate

This calculator uses just a few inputs. Adjust them to see how each variable shifts the answer.

Risk & benchmark gauge

Current band

Low

Total In: $155,000

0255075100

LowModerateStrongMaximum

Industry benchmarks

Irr14.41
Unique SolutionYes
Total In$155,000
Total Out-$100,000
Net Gain$55,000
Npv$20,119

Key insights

Pre-tax contributions reduce taxable income

Every dollar to 401(k), HSA, or traditional IRA reduces taxable income at your marginal bracket — typically 12-32% federal.

Sensitivity testing

Adjust each input by ±10% to find the most impactful variable — that's the one to focus your real-world decisions on.

Recommended actions(4)

Test the realistic range of each input

High priority

Try the lowest and highest realistic value for each input. The spread of results is the range you should actually plan for — point estimates lie.

Impact: Reveals which inputs matter most and where uncertainty hides.

Compare against published benchmarks

Medium priority

Whatever you're calculating, there's likely an industry benchmark for it. Google "[topic] average" or "[topic] median" to sanity-check the result.

Save or download a copy

Medium priority

For calculators that offer it, use "Download report (PDF)" to keep a snapshot. Otherwise screenshot the inputs + result before navigating away.

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This tool is for educational purposes only and does not constitute financial, tax, or investment advice. Consult a qualified financial professional for advice specific to your situation.

What is Internal Rate of Return?

IRR is the discount rate at which a series of cash flows has a net present value of exactly zero. Put less formally: the annual rate at which your money grew, given how much went in, how much came back, and — crucially — when.

Timing is what IRR adds over a simple return calculation. Two investments returning the same total have very different IRRs if one pays back early and the other pays back late, and the early one is worth more because that money can be doing something else.

There is no closed-form solution. IRR is found by trial and improvement — this calculator uses Newton-Raphson — and for some cash flow patterns it does not exist at all.

The critical thing to understand before trusting the number is its reinvestment assumption. IRR implicitly assumes every distribution is reinvested at the IRR itself, which is how a genuinely good deal reports an implausibly good headline.

The formula — how to calculate Internal Rate of Return

Find r such that: Σ [ CFₜ ÷ (1 + r)ᵗ ] = 0 for t = 0 … n NPV at rate d = Σ [ CFₜ ÷ (1 + d)ᵗ ] MIRR = ⁿ√( FV of positive flows at reinvestment rate ÷ −PV of negative flows at finance rate ) − 1

CF₀: = the initial investment, entered as a negative number
r: = the internal rate of return — the unknown being solved for
MIRR: = states the reinvestment rate explicitly instead of assuming it equals the IRR

A unique IRR exists only when the cash flow signs change exactly once. A stream that goes negative, positive, then negative again can have two mathematically valid IRRs, or none.

Step-by-step example

01Invest $100,000, then receive $20,000, $25,000, $30,000, $35,000 and $45,000 over five years.
02Total received: $155,000. Net gain: $55,000, or 55% on the original outlay.
03But that 55% ignores timing entirely. Solving for the rate that makes NPV zero gives an IRR of about 14.4% a year — higher than the simple annualised gain, because much of the money comes back early and is free to work elsewhere.
04At an 8% cost of capital the NPV is $20,119 — comfortably positive, so the project clears the hurdle.
05Now the reinvestment question. MIRR, assuming distributions are redeployed at 8% rather than at 14.4%, comes out at 12.0%.
06The 2.4-point gap is the assumption doing the work. IRR credited you with reinvesting each payment at 14.4%; MIRR only assumes 8%. On a deal reporting a 40% IRR the same gap can be ten points or more, which is why private equity returns quoted as IRR deserve a second look.

The reinvestment assumption, stated plainly

This is the single most important thing to know about IRR and the least frequently mentioned.

The arithmetic of IRR discounts every cash flow at the IRR itself. Mathematically that is equivalent to assuming each interim distribution, once received, earns the IRR until the end of the project.

For a project with a 12% IRR that is broadly plausible — you can probably find something returning 12%. For a project reporting a 45% IRR it is close to fantasy: it assumes that every distribution can immediately be redeployed at 45%, which, if true, would mean you had found an unlimited supply of extraordinary investments.

The consequence is that IRR systematically flatters investments that return cash early. The earlier the money comes back, the longer the assumed reinvestment period, and the more of the headline figure rests on an assumption nobody checks.

MIRR fixes this by requiring you to state the reinvestment rate. It is almost always lower than IRR and almost always closer to what you actually experienced.

This matters commercially because IRR is the standard reporting metric in private equity and real estate — precisely the asset classes where distributions arrive irregularly and the reinvestment assumption does the most work.

IRR can be gamed by timing alone

A fund that uses a credit line to delay calling investor capital, then calls it late and exits quickly, can report a substantially higher IRR on identical underlying performance — because IRR is sensitive to how long the money was formally committed. This is legal, disclosed, and widespread. It is also why sophisticated investors ask for a multiple on invested capital alongside the IRR: MOIC cannot be manipulated by timing in the same way.

When IRR has no answer, or several

IRR is the root of a polynomial, and polynomials can have multiple roots or none in the range that makes sense.

Descartes' rule of signs gives the practical test: the number of possible positive IRRs is at most the number of sign changes in the cash flow sequence. One sign change — money out, then money in — guarantees at most one IRR, and that is the normal investment shape.

Two or more sign changes open the door to multiple solutions. A mining project that requires a large closure cost at the end goes negative, positive, negative, and can produce two mathematically valid IRRs, say 10% and 40%. Neither is more correct than the other, and reporting either alone is misleading.

Some streams have no real IRR at all. If a project never returns more than it consumed, no discount rate makes the NPV zero.

This calculator flags when the sign changes more than once, and returns no answer rather than a number when the solver fails to converge. A calculator that always produces a figure is not being more helpful — it is hiding a failure.

When IRR is ambiguous, NPV is not. NPV has exactly one value at any given discount rate, which is the main argument for using it as the primary decision tool.

IRR against NPV, and which decides

The two answer different questions and the standard finance answer is unambiguous: NPV decides, IRR ranks.

NPV tells you how much value a project creates in today's money at your cost of capital. A positive NPV means proceed. It is stated in currency, it is unique, and it scales with the size of the project.

IRR tells you the rate, which is comparable across projects of different sizes and durations, and is far more intuitive to communicate. "This returns 15%" lands in a way "this creates $2.3 million of NPV" does not.

They disagree in two situations, and when they do, NPV is right.

The first is scale. A small project returning 50% on $10,000 has a higher IRR than a large one returning 15% on $10 million, but the second creates vastly more value. IRR is blind to size.

The second is timing profile. A project that returns everything quickly can show a higher IRR than one that compounds for longer, even where the second is worth far more in absolute terms.

The practical resolution most firms use: screen on NPV, communicate in IRR, and check MIRR whenever the IRR looks too good.

NPV —: net present value at your chosen discount rate. Positive means the project clears the hurdle. Unique, and stated in money.
IRR —: the rate at which NPV equals zero. Comparable across deals, but assumes reinvestment at itself.
MIRR —: modified IRR, with the reinvestment rate stated explicitly. Lower and more honest.
MOIC —: multiple on invested capital — total returned over total invested. Ignores timing entirely, which is exactly why it is a useful cross-check on IRR.
Hurdle rate —: the minimum acceptable return, usually the cost of capital. IRR above it means proceed.
Payback period —: how long until you get your money back. Crude, ignores everything after, and still the first question most investors ask.

Getting the inputs right

The arithmetic is only as good as the cash flow schedule, and the schedule is where most errors live.

Use actual cash, not accounting profit. Depreciation is not a cash flow; a capital expenditure is, in the period it is paid.

Put the initial investment in period zero as a negative number, and be consistent about period length. Annual flows give an annual IRR; monthly flows give a monthly IRR, which must be annualised as (1 + r)¹² − 1 rather than multiplied by twelve.

Include the terminal value. For a property or a business, the sale proceeds in the final period usually dominate the IRR, and omitting them understates the return dramatically.

Be honest about timing. A cash flow received in month eleven entered as year one is a real distortion, and IRR is sensitive to exactly this.

And use pre-tax or post-tax consistently. Comparing a pre-tax IRR against a post-tax hurdle rate is a common and expensive mismatch.

Common mistakes to avoid

Trusting a high IRR without checking MIRR. The gap between them is the reinvestment assumption.
Choosing between projects on IRR alone, which ignores scale.
Ignoring the warning when signs change more than once — multiple IRRs may exist.
Annualising a monthly IRR by multiplying by 12 instead of compounding.
Omitting the terminal or sale value in the final period.
Using accounting profit rather than cash flow.
Comparing a pre-tax IRR against a post-tax hurdle rate.
Accepting a fund IRR without also asking for the multiple on invested capital.

Frequently asked questions

Sources & references

SEC Investor.gov — Evaluating investments

Written and fact-checked by the CalcProLabs Editorial Team. Read our calculation methodology and editorial policy.

Last updated August 7, 2026