Retirement Calculator
U.S. Flagship #10Investing & ReturnsSee if your nest egg will last.
Your retirement plan
Your projection
70% how funded you are + 30% how long the money lasts.
What it takes to hit your goal
Each figure is the single change that, on its own, would fully fund your target.
Monte Carlo & probability of success
Markets never hand you a smooth average. This replays your plan across many random return paths to estimate the odds it actually holds up — not just one tidy projection.
Share of 1,000 simulated lifetimes whose money funds the plan to the end.
Range of outcomes over time
The shaded band spans the 10th to 90th percentile and the solid line is the median path. A horizontal dashed line marks the target portfolio; the vertical line marks your retirement age.
Distribution of outcomes
How often each ending balance came up across the simulated paths, in today's money.
Percentile outcomes
Where your plan lands across the simulated range.
| Outcome | Pessimistic | Median | Optimistic |
|---|---|---|---|
| Nest egg at retirement | $1,018,808 | $1,820,418 | $3,132,920 |
| Ending balance (today's $) | $0 | $0 | $1,282,628 |
Pessimistic is the 10th percentile, optimistic the 90th — a wider gap means more uncertainty.
Savings growth
Your balance, the money you put in, and its value in today's prices as you save.
Portfolio lifecycle
The full arc — building up to retirement, then drawing down through it.
What builds your nest egg
Where the final balance comes from.
Drawdown in retirement
How the portfolio is spent down once the income starts.
Retirement income sources
Who pays for the first year of retirement.
- Portfolio$83,903
- Social Security$41,951
Inflation and your income goal
The same lifestyle costs more every year you wait.
Future vs today's money
Big future numbers shrink once inflation is stripped out.
- Nest egg (future)$1,985,529
- Nest egg (today)$946,586
- Target (future)$2,097,568
- Target (today)$1,000,000
Projected vs target
How close your projection lands to the target portfolio.
- Projected$1,985,529
- Target$2,097,568
Annual savings projection
| Age | Paid in | Balance | Today's $ |
|---|---|---|---|
| 35 | $75,000 | $75,000 | $75,000 |
| 39 | $129,405 | $158,577 | $143,663 |
| 44 | $203,761 | $305,443 | $244,577 |
| 48 | $268,780 | $468,193 | $339,637 |
| 52 | $339,159 | $684,434 | $449,806 |
| 56 | $415,340 | $970,249 | $577,673 |
| 61 | $519,456 | $1,457,618 | $767,049 |
| 65 | $610,499 | $1,985,529 | $946,586 |
Portfolio projection (full lifecycle)
| Age | Future $ | Today's $ |
|---|---|---|
| 35 | $75,000 | $75,000 |
| 41 | $210,897 | $181,856 |
| 47 | $423,032 | $314,548 |
| 54 | $817,469 | $511,350 |
| 60 | $1,346,449 | $726,262 |
| 66 | $1,989,101 | $925,160 |
| 72 | $1,962,426 | $787,064 |
| 79 | $1,787,797 | $603,209 |
| 85 | $1,455,457 | $423,454 |
| 91 | $878,665 | $220,438 |
Withdrawal schedule
| Age | Withdrawal | Balance | Today's $ |
|---|---|---|---|
| 66 | $83,903 | $1,989,101 | $925,160 |
| 70 | $92,613 | $1,981,568 | $834,976 |
| 73 | $99,734 | $1,948,376 | $762,370 |
| 77 | $110,088 | $1,857,425 | $658,429 |
| 80 | $118,552 | $1,746,030 | $574,748 |
| 84 | $130,860 | $1,525,581 | $454,952 |
| 87 | $140,921 | $1,294,611 | $358,507 |
| 91 | $155,551 | $878,665 | $220,438 |
Where the nest egg comes from
| Metric | Value |
|---|---|
| Starting savings | $75,000 |
| Your contributions | $389,454 |
| Employer contributions | $146,045 |
| Investment growth | $1,375,030 |
| Total paid in | $610,499 |
Income projection (today's money)
| Source | Per year | Per month |
|---|---|---|
| Portfolio | $40,000 | $3,333 |
| Social Security | $20,000 | $1,667 |
| Other income | $0 | $0 |
| Total income goal | $60,000 | $5,000 |
Inflation-adjusted balance
| Age | Future $ | Today's $ |
|---|---|---|
| 35 | $75,000 | $75,000 |
| 39 | $158,577 | $143,663 |
| 44 | $305,443 | $244,577 |
| 48 | $468,193 | $339,637 |
| 52 | $684,434 | $449,806 |
| 56 | $970,249 | $577,673 |
| 61 | $1,457,618 | $767,049 |
| 65 | $1,985,529 | $946,586 |
Retirement summary
| Metric | Value |
|---|---|
| Years to retirement | 30 |
| Net return (after fees) | 6.60% |
| Real return (after inflation) | 4.00% |
| Nest egg (future $) | $1,985,529 |
| Nest egg (today's $) | $946,586 |
| Target portfolio (future $) | $2,097,568 |
| Monte Carlo success | 45% |
| How long it lasts | Lasts for life |
| Readiness | 96 · On track |
FIRE milestones
Financial-independence targets in today's money, based on your spending and withdrawal rate.
How this calculator works
A transparent model you can audit: a deterministic two-phase projection for the headline figures, plus an optional Monte Carlo overlay for the odds. Every figure is shown in both future and today's money.
Accumulation
Your balance compounds monthly at your return minus fees; contributions step up each year by your growth rate, with any employer money on top.
Decumulation
In retirement the portfolio funds the income your other sources don't, indexed to inflation and growing at your retirement return until it is exhausted or outlives you.
Sizing the target
Your income goal is inflated to your retirement year; after Social Security and other income, the rest is divided by your safe withdrawal rate.
Readiness score
An original 0–100 blend: 70% how funded you are versus the target, 30% how long the money lasts against your plan-through age.
Monte Carlo
An optional overlay replays the plan across 1,000 random return paths around your expected return, scaled by your volatility, to estimate the probability it lasts. A fixed seed keeps the result stable; at 0% volatility it matches the deterministic projection exactly.
Optional retirement tax
When on, withdrawals are grossed up by 1 ÷ (1 − rate): the income goal is after-tax and the portfolio is assumed tax-deferred, like a traditional 401(k) or IRA. The FIRE tiles stay pre-tax; only the target portfolio, drawdown and supportable income carry the tax.
Estimates for planning only, not advice. Real returns, inflation and lifespans vary; revisit your plan as they change.
A worked example
Take a 40-year-old with $150,000 saved who adds $1,000 a month, expects 6% growth and 2.5% inflation, and wants $50,000 a year (today's money) on top of $20,000 from Social Security, drawing at 4% and planning to age 90. Over 25 years the nest egg reaches about $1.32 million — roughly $712,000 in today's money. The portfolio only has to cover $30,000 a year, so the target is $750,000 in today's dollars; the plan lands 94.9% funded with a $70,000 gap and a readiness score of 96. Lifting the monthly contribution to about $1,104, or working to 67, closes it.
With your numbers
Your plan projects a $1,985,529 nest egg ($946,586 in today's money) against a $2,097,568 target — 95% funded, for a readiness score of 96 (on track). Saving about $884/month would fully close the gap.
Key terms
Educational estimates only — not financial advice. Figures depend on assumptions that will not hold exactly.
Related calculators
Dig into the building blocks behind your retirement projection.
Know what this estimate is based on
- Jurisdiction
- United States retirement-planning context
- Rules and time period
- Long-range projection; returns, inflation, fees, taxes, and Social Security are user-entered assumptions rather than live forecasts.
- Scope and limitations
- Long-range scenario, not a forecast or investment recommendation. Returns, inflation, fees, taxes, Social Security, withdrawal rates, sequence risk, and longevity can materially change the outcome.
- Source links checked
- Jul 30, 2026
Built and regression-tested by Smart Tools Lab. It has not been individually reviewed by a licensed financial, tax, or legal professional.
How to use
- 01
Enter your age today, the age you plan to retire, and the age your plan should fund through, then add the balance you have already invested. These anchor both the accumulation and the drawdown horizons.
- 02
Enter how much you save each month or year, a salary-growth rate to step those deposits up over time, and any employer contribution. Then set your expected return, inflation, and the investment fee that is subtracted from the return.
- 03
Type the yearly income you want in retirement in today's dollars, choose a safe withdrawal rate, and enter any Social Security, pension, or other income. The tool inflates the remaining need to your retirement year and divides it by the rate to size your target.
- 04
Review your projected nest egg in both nominal and today's dollars, the funding gap against the target, and your 0-100 readiness score. The 'what it takes' panel then shows the contribution, return, or retirement age that would close any shortfall.
- 05
Open the advanced options to add a one-time lump sum, set return volatility, tune the Lean and Fat FIRE budgets, or switch on a tax on withdrawals, then read the Monte Carlo panel for the probability your plan survives random markets across a thousand simulated lifetimes.
Formula
Retirement income gap = max(0, desired income − Social Security − other income). Required portfolio = income gap ÷ safe withdrawal rate. If withdrawals are taxed, first gross up the gap: gross income gap = net income gap ÷ (1 − tax rate). During accumulation the engine compounds the balance monthly at the net annual return (expected return minus the investment fee), adds contributions at month-end and increases those contributions annually by the salary-growth rate.
Example
You want 60,000 a year in today's money and expect 20,000 from Social Security, with no other income or withdrawal tax. The portfolio must provide 40,000 a year. At a 4% safe withdrawal rate, the real target is 40,000 ÷ 0.04 = 1,000,000. The calculator then projects whether your current balance and contributions can reach that target by retirement.
Definitions
- Safe withdrawal rate
- The starting annual withdrawal as a percentage of the retirement portfolio; it converts an income need into a target balance.
- Net return
- Expected investment return after subtracting the annual investment fee used by the projection.
- Real value
- A future amount deflated into today's purchasing power using the inflation assumption.
- Income gap
- The part of desired retirement income that Social Security, pensions and other guaranteed income do not cover.
- Depletion age
- The first age at which the simulated retirement balance can no longer fund the planned withdrawal.
Good to know
What a retirement calculator actually does
A retirement calculator models the two halves of a working life's money story: the years you spend building a pool of savings, and the years that pool has to pay you back. The first half, accumulation, runs from today to the day you stop working. This tool steps through it month by month, growing your current balance and each fresh contribution at your expected return minus the investment fee, while letting those contributions rise a little every year as your salary grows and folding in any employer money. The second half, decumulation, runs from your retirement date to the age you want the plan to cover. Here the projected nest egg has to deliver a paycheque you no longer earn, indexed to inflation so it keeps its buying power, drawn from a portfolio that now grows at a gentler retirement return until either it runs dry, at the depletion age, or it carries you through for life. The headline projection is deterministic, so the same inputs always produce the same numbers and you can change one assumption and see exactly what moved; an optional Monte Carlo overlay then stress-tests that plan across a thousand random market paths to report the odds it actually survives. Every headline number appears twice, once in nominal future dollars and once deflated to what it would buy today, because a seven-figure balance decades out is rarely the lifestyle it sounds like. Tying it all together is a readiness score from 0 to 100 that is unique to this calculator: 70% of it reflects how close your projected nest egg comes to the target it needs, and 30% reflects how long the money is set to last across your retirement, sorting you into off-track, building, on-track, or fully funded. Read the whole projection as a careful map of one particular set of assumptions, not a guarantee about markets no one controls, and use it to test how today's choices ripple decades forward.
How much you need: income replacement and your target portfolio
Planning for retirement starts with a deceptively simple question: how much annual income will you want once the salary stops? Many people anchor on replacing a share of their final pay, often somewhere around two-thirds to four-fifths, on the logic that some costs fall away once commuting, payroll taxes, and saving itself disappear, though health and leisure spending can push the other way. This calculator asks you to name that figure directly, in today's dollars, so you are reasoning about a lifestyle you can actually picture rather than an abstract future sum. From there the arithmetic is clear. Not all of that income has to come from your invested savings: Social Security, a pension, rental income, or anything else you expect is subtracted first, and only the leftover, the portfolio's share of the bill, needs to be funded by your nest egg. Divide that net annual need by your chosen safe withdrawal rate and you have the target portfolio, the lump sum large enough to throw off that income year after year. Take the worked example built into this guide: a desired $50,000 a year, with $20,000 covered by Social Security, leaves the portfolio responsible for $30,000. At a 4% withdrawal rate that points to a target of $750,000 in today's money, which the engine then inflates to $1,390,458 in the dollars of the actual retirement year. Your projected nest egg is measured against that target to produce a funding ratio and the dollar gap or surplus between the two. Seeing the target broken down this way is clarifying, because it shows that the number you are chasing is driven as much by how much outside income you have lined up and how aggressively you intend to draw down as by the headline lifestyle you hope to fund.
The safe withdrawal rate and the 4% rule
The safe withdrawal rate is the percentage of your portfolio you take in the first year of retirement, after which you adjust that dollar amount for inflation each year and keep going, ideally without running out. It is the hinge of the whole plan, because the target portfolio is simply your net income need divided by this rate: a lower rate demands a bigger pot, a higher one a smaller pot but a riskier ride. The 4% figure most people have heard traces back to work by the financial adviser William Bengen in 1994 and to the later Trinity study, both of which examined historical US market returns and asked what starting withdrawal a portfolio of stocks and bonds could have survived across long retirements, including ones that began just before brutal downturns. It emerged as a rate that held up across most of those historical windows for a 30-year horizon. It is genuinely useful as a rule of thumb, but it carries several caveats and was never meant as a promise. It rests on a particular history the future need not repeat, especially from starting points of low yields or stretched valuations. It assumes a roughly 30-year retirement, so someone retiring early or expecting to live into their late nineties may need to draw a more cautious 3% to 3.5%. And it is acutely exposed to the order in which returns arrive, since a steep loss in the opening years does outsized damage to a pot you are also drawing down. This tool lets you set whatever rate you judge prudent rather than baking in any single answer, and reports the supportable income your projected savings could sustain at that rate. Treat the figure you choose as a dial that trades security against the savings required, not as a setting that makes any withdrawal level truly risk-free.
Inflation and real vs nominal retirement income
Inflation is the quiet force that makes retirement planning genuinely hard, because the same income that feels comfortable on your first day of retirement buys steadily less every year that follows, and retirements now stretch across decades. At even a mild 2.5% a year, prices roughly double over 30 years, so a fixed payment would shed about half its purchasing power across a long retirement. This calculator handles the problem in two deliberate ways. First, you enter your desired income in today's dollars and the engine inflates it to your retirement year and then keeps stepping each annual withdrawal up with prices, so the plan funds a constant standard of living rather than a constant count of dollars. Second, every result is shown twice: a nominal figure in the future dollars actually paid, and a real figure deflated back to what it would buy today. The gap between the two is striking. In the worked example, a projected nest egg of $1,320,070 in nominal dollars is worth only $712,033 in today's purchasing power after 25 years of saving, and a target that looks like $1,390,458 in retirement-year dollars is really the same $750,000 we set out to fund. Neither figure is wrong; they answer different questions, and seeing both keeps you from being either dazzled or alarmed by a large nominal total. The practical lessons are worth absorbing: any income source that does not rise with prices, such as many private pensions, silently shrinks in real terms and should be treated with caution, and your assumed investment return matters far less than how far it clears inflation. A return that merely matches inflation leaves you no real progress at all, which is why the calculator also reports your real return, the growth that genuinely expands what your money can buy.
Social Security, pensions and other income
Your invested savings rarely have to shoulder the entire cost of retirement, and accounting honestly for the other income you expect is one of the biggest levers in the whole plan. Social Security, a workplace or government pension, annuity payments, rental income from a property, part-time earnings, or proceeds from a business sale all arrive independently of your portfolio, and every dollar of it is a dollar your nest egg does not have to generate. This calculator lets you enter Social Security and a separate other-income line, both in today's dollars, and subtracts them from your desired income before sizing anything. The effect is powerful because of how the target is built. In the worked example, a $50,000 income goal with $20,000 of Social Security leaves the portfolio responsible for just $30,000, and at a 4% withdrawal that shrinks the target from a daunting $1,250,000 to a far more reachable $750,000 in today's money. Guaranteed lifelong income also does something a portfolio cannot: it does not run out and does not care about market crashes, so it directly blunts both longevity risk and sequence risk for the share of your spending it covers. Even so, these sources deserve realistic treatment. Social Security estimates depend on your earnings record and the age you claim, and claiming later raises the monthly amount; pensions vary in whether they keep pace with inflation, and one that does not will quietly erode in the real terms this tool emphasises. Because the figures are entered in today's dollars and inflated alongside everything else, the calculator assumes they broadly keep up with prices, so if a pension is fixed in nominal terms you may want to enter a more conservative figure. Used carefully, the other-income inputs often reveal that a goal which looked out of reach is closer than the headline number suggested.
Sequence-of-returns and longevity risk
Two dangers threaten a plan that looks healthy on paper, and neither shows up in the smooth projection above, so it is worth understanding both before you lean on a single line of numbers. The first is sequence-of-returns risk: the order in which good and bad years arrive matters enormously once you start drawing an income, even though it makes no difference at all while you are still saving. A steep market fall in the opening years of retirement forces you to sell more shares to fund the same withdrawal, leaving fewer behind to recover when prices eventually rebound; the identical fall arriving a decade later, after years of growth, does far less harm because your earlier withdrawals were taken from a rising balance. The deterministic projection assumes one constant retirement return, so its smooth line cannot show that effect at all; this is exactly the gap the optional Monte Carlo overlay fills, scattering strong and weak years at random so the unlucky early-loss paths show up directly in the success probability rather than hiding behind an average. The usual defences are practical: hold a year or two of spending in cash so a slump never forces a sale, and stay willing to trim withdrawals when returns disappoint. The second danger is longevity risk, the plain possibility of living longer than your savings last. Setting the plan to a life expectancy of, say, 90 is a planning convenience, not a promise about your own lifespan, and roughly half of people outlive any average you pick. Because the income goal is inflation-indexed every single year, a long life also compounds the bill: the same lifestyle quietly demands more dollars each year, and any pension or annuity that does not rise with prices buys steadily less. Build in margin, revisit the figures regularly, and treat a generous longevity buffer as cheap insurance against the one outcome in retirement you can never undo once it has arrived.
The FIRE family: Lean, Barista, Coast, full and Fat
FIRE, short for financial independence and retiring early, is a family of targets rather than a single number, and this tool expresses every one of them in today's dollars so you can weigh them honestly side by side. The headline FIRE number is your annual expenses divided by your safe withdrawal rate; at a 4 percent rate that is the familiar twenty-five-times-spending figure, the pot from which your chosen withdrawal funds your whole lifestyle indefinitely. Lean FIRE applies the same arithmetic to a deliberately trimmed budget, multiplying your expenses by a leanness factor such as 0.7, giving the smaller pile that supports a more frugal life and can be reached years sooner. At the opposite end, Fat FIRE multiplies your expenses upward by a factor you choose, perhaps two or three, to bankroll a deliberately generous retirement with room for travel, housing and healthcare; the trade is a far larger pot that takes longer to build. Barista FIRE recognises that many who step away from full-time work still earn something part-time; it divides only the expenses your portfolio must cover, your spending minus that part-time income, by the withdrawal rate, so even modest ongoing earnings sharply shrink the savings you need. Coast FIRE is the most widely misread of the set, so take it slowly: it is not a contribution and not your final target, but the amount you would need invested today so that, with no further saving whatsoever, ordinary growth carries it up to the full FIRE number by the age you retire. The tool finds it by discounting the FIRE number back along your real return over the years remaining, which is why a younger saver's Coast figure is so much smaller, since decades of compounding do the rest of the work unaided. Reaching your Coast number is a genuine milestone: it means the saving job is essentially finished and you could, in principle, cover only your current costs from here and still arrive fully funded. Read the five together as a ladder, from the lean and early to the rich and unhurried, and let them frame the trade-off between how much you spend, how much you keep earning, and how soon you stop.
Reading your readiness score and funding gap
The readiness score compresses your whole plan into one figure from 0 to 100, and it is built specifically for this tool rather than borrowed from any official standard, so it pays to know exactly what feeds it. Two questions decide the number. First, how big is your projected nest egg relative to the target your desired income implies, which is the funding ratio, capped at 1 so that overshooting the goal cannot inflate the result. Second, how long does the money last relative to the length of your retirement, the longevity ratio, also capped at 1 because lasting for life is the most credit that part can earn. The score weights the first at seventy percent and the second at thirty, on the view that having enough set aside matters more than the precise number of years a given balance happens to stretch. In the worked example, the plan is 94.9 percent funded and the money lasts for life, so the arithmetic is 0.7 times 0.949 plus 0.3 times 1, which rounds to a readiness of 96. The bands turn the number into plain language: below 50 is off-track and needs real change, 50 to 79 is building and pointed the right way, 80 to 99 is on-track with a manageable gap, and 100 or more is fully funded with room to spare. A score in the nineties paired with a small funding shortfall, as in that example, is reassuring rather than alarming, because it means you are close and the levers to cover the rest are modest. Since both inputs are capped, the measure rewards a durable, lasting plan over a merely large one, and it will not let a huge surplus disguise a plan that runs dry early under a higher spending goal. Treat it as a quick health check, then look beneath it at the funding ratio and the depletion age for the real detail.
Closing the gap: contributions, returns and time
When the projection lands short of your target, the natural question is what it would actually take to get there, and the tool answers directly through six reverse solves instead of leaving you to guess. Rather than only projecting a result from your inputs, it can hold the goal fixed and work backwards for the input that reaches it. It will find the required monthly contribution and the equivalent required annual contribution, the required gross return your plan quietly demands, the earliest retirement age at which the numbers work, the required fund, which is simply the target your income goal implies, and the supportable income, meaning what your projected nest egg can genuinely pay, worked out as the pot times your withdrawal rate plus any other income. Seeing the same goal from these different angles turns a vague shortfall into concrete choices. In the worked example the plan sits at 94.9 percent funded, and the calculator spells out three clean routes to full funding: contribute $1,104 a month rather than $1,000, or earn 6.27 percent a year rather than 6, or push the retirement age out from 65 to 67. Each route closes the very same gap from a different direction, and each carries its own cost, whether a little more out of every paycheque, a little more investment risk, or a little more time spent working, so you can choose the trade-off you find easiest to live with, or blend them. The contribution levers are usually the most dependable, since they rest on your own behaviour rather than on markets cooperating; reaching for a higher return means accepting more volatility, and a required return that comes back implausibly high is a signal to lower the goal or lengthen the horizon, not to chase risk. Working backwards like this keeps the plan anchored in what you can truly control.
Monte Carlo simulation and your probability of success
A single expected return tells a reassuring story, but it is a story markets rarely honour, because real returns arrive in a jagged, unpredictable order that an average quietly smooths away. The Monte Carlo overlay exists to put that jaggedness back. Instead of one tidy path it replays your entire plan across a thousand simulated lifetimes, drawing each year's return at random from a bell curve centred on your expected return and spread by a volatility you set, then accumulating and drawing down exactly as the deterministic model does. From those thousand endings it reports two probabilities worth distinguishing. The success probability is the share of paths whose money funds your inflation-rising income all the way through your plan-through age without running dry; this is the headline, the closest thing the tool offers to a plain answer to will my money last. The goal probability is narrower, the share of paths whose nest egg simply reaches the target by your retirement age, which speaks to the saving phase alone. The fan chart turns the spread into a picture: a shaded band from the 10th to the 90th percentile with the median path drawn through it, so you can see both the typical outcome and how widely fortune scatters around it. Two design choices are worth knowing. A fixed random seed means the percentage does not flicker each time you nudge an input, so you can compare scenarios honestly, and at zero volatility every path collapses back onto the deterministic projection, a useful sanity check. One result often surprises people: the median Monte Carlo balance sits below the deterministic figure even when the average return is identical, because volatility drags the middle of a compounding series downward, a real effect rather than a glitch. Read a probability in the high eighties or nineties as a robust plan, and a lower one as an honest nudge to save more, spend less, retire later, or temper your assumptions.
Taxes in retirement and the tax-deferred gross-up
Most retirement calculators quietly ignore tax, which flatters every projection, because the income you actually get to spend is what is left after the taxman takes a share. This tool keeps tax optional and, by default, off, so the headline stays simple, but switching it on adds an honest and often sobering layer. The key insight is the kind of account your savings sit in. Money in a traditional, tax-deferred 401(k) or IRA was never taxed going in, so every dollar you withdraw in retirement is taxed as income on the way out; to actually spend a target amount you must withdraw more than that amount and hand the difference to tax. The calculator models this by treating your income goal as an after-tax figure and grossing the required withdrawal up by one divided by one minus your effective rate, so a 25 percent rate turns a 30,000 spending need into a 40,000 gross withdrawal. That larger draw flows straight through the plan: it raises the target portfolio you must accumulate, increases the yearly drawdown, and reduces the after-tax income your projected savings can genuinely support. Two deliberate boundaries keep the model clear. The FIRE numbers are left pre-tax, so they retain their familiar twenty-five-times-spending meaning rather than shifting under you, and any Social Security, pension, or other income you enter is taken as an already-net figure, so the gross-up applies only to portfolio withdrawals. The rate you choose is an effective blended rate across your whole drawdown, not a marginal bracket, and it suits pre-tax balances rather than Roth accounts, which are withdrawn tax-free, or ordinary taxable accounts, where only gains are taxed. Used thoughtfully it answers a question the pre-tax headline cannot: how much must I really amass so that what reaches my pocket matches the life I planned.
Lump sums, windfalls and the power of timing
Saving is rarely a perfectly even drip; real lives include the occasional flood, an inheritance, the sale of a house or business, a maturing bond, a large bonus, and those one-off sums can move a retirement plan more than years of routine contributions. The one-time contribution input lets you place such a lump precisely, both its amount and the age you expect to invest it, and the engine then injects it into your savings at that point and compounds it through every remaining year to retirement at your net return. Timing is the lesson the tool makes vivid. A windfall invested early has decades to multiply, so a sum dropped in at forty can finish far larger than the identical sum added at sixty, where it barely has time to grow before you need it; the earlier the better is not a slogan here but arithmetic you can watch by sliding the age. The contribution breakdown lists the lump on its own line, kept distinct from your regular saving and any employer money, so you can see exactly how much of the final nest egg traces to that single event rather than to habit. It also feeds the reverse solvers honestly: because the extra capital is already working in the projection, the contribution, return, or retirement age the plan still needs to close any gap is calculated net of the windfall, not on top of it. If a lump is uncertain, model it conservatively or leave it out and treat it as upside, since planning to need a windfall that may not arrive is its own quiet risk.
Common retirement-planning mistakes
The errors that derail retirement plans are remarkably consistent, and most belong to the save-then-spend journey rather than to saving alone. The first is ignoring sequence-of-returns risk, planning around an average return as though the bad years will politely wait until late, when in truth a downturn in the first few years of drawing income does outsized and lasting damage. The second is anchoring on nominal figures and forgetting inflation; a seven-figure balance sounds like wealth, but after decades of rising prices its real purchasing power is far smaller, which is exactly why every result here is shown in today's money alongside the headline. The third is treating the four percent withdrawal rule as a cast-iron guarantee rather than the rule of thumb it really is, a useful starting point drawn from history that can still fail amid weak returns, high inflation or an unusually long retirement, and so deserves caution rather than blind faith. The fourth is underestimating longevity, setting the plan to a comfortable-sounding age while quietly assuming you will not be one of the many who live well beyond the average and outlast a pot built for a shorter life. The fifth is leaning on fixed income that does not keep pace with prices: a pension or annuity that never rises buys a little less every year, slowly hollowing out a plan that looked solid at the start. The sixth is retiring on the eve of a downturn with no cushion, leaving yourself forced to sell depressed assets just to eat. And the last is setting the plan once and never revisiting it, when returns, inflation, health and goals all drift over the years. The antidotes are unglamorous but reliable: keep a cash buffer, stay flexible about spending in weak years, judge everything in real terms, build in a longevity margin, and revisit the numbers often so the plan bends with reality instead of breaking against it.
Frequently asked questions
How much do I need to retire on?
There is no single figure; it depends on the income you want and how much of it your own portfolio must cover. Decide the yearly spending you want in today's dollars, subtract guaranteed income like Social Security or a pension, then divide what's left by your safe withdrawal rate. In the worked example a $30,000 portfolio need at a 4% rate sizes a $750,000 target in today's money.
What does the safe withdrawal rate, or 4% rule, actually mean?
The safe withdrawal rate is the share of your portfolio you take in the first retirement year, then adjust upward for inflation. The familiar 4% figure traces to Bengen's 1994 work and the Trinity study, which found that rate historically lasted about thirty years. Treat it as a rule of thumb, not a promise: low starting yields, a longer life, high fees, or an early downturn can all make a gentler rate wiser.
What is the difference between real and nominal figures?
Nominal figures are the actual dollar amounts you will see on a future statement; real figures are those same amounts deflated to what they would buy today. Because prices rise, a large nominal nest egg buys less than it appears to. In the example the $1,320,070 projected balance is worth $712,033 in today's money. Every headline here is shown both ways, so judge your plan by the real, spendable result.
How is the readiness score computed?
It is this tool's own transparent blend, not an industry standard. Seventy percent comes from your funding ratio, the projected nest egg divided by the target and capped at one, and thirty percent from longevity, the years your money lasts divided by your years in retirement, also capped. Scores below 50 are off-track, 50 to 79 building, 80 to 99 on-track, and 100 means fully funded. The example plan scores 96.
What do FIRE, Coast FIRE and Barista FIRE mean?
FIRE stands for financial independence, retire early. Your FIRE number is annual expenses divided by your withdrawal rate, the portfolio meant to sustain that spending long-term. Lean FIRE applies a leaner expense budget; Barista FIRE subtracts part-time earnings before dividing, so a smaller pot suffices. Coast FIRE is the amount invested today that would grow on its own, with no further saving, to your full FIRE number by retirement. All are quoted in today's dollars.
Should I include Social Security?
Yes. Unlike some calculators, this one lets you enter Social Security and other income, such as a pension, rentals, or an annuity, in today's dollars, and subtracts them from your desired income. Only the remaining need is divided by your withdrawal rate, so your portfolio target reflects only what savings must actually cover. In the example, $20,000 of Social Security trims a $50,000 goal to a $30,000 portfolio need. If you are unsure of your benefit, estimate conservatively.
What should I do about a funding gap?
A gap means your projected nest egg falls short of the target. The 'what it takes' panel quantifies your options: save more, earn more, or work longer. In the worked example, closing a $70,389 gap takes saving $1,104 a month instead of $1,000, earning 6.27% instead of 6%, or retiring at 67 rather than 65. You can also lower the income you target or trim fees. Combining smaller moves is usually gentler than relying on any one.
How does sequence-of-returns risk work?
It is the danger that the order of returns, not just their average, decides whether your money lasts. Because you withdraw a fixed, inflation-rising income each year, a steep loss in your first retirement years sells more shares at depressed prices, leaving fewer to recover when markets rebound, far more damaging than the identical loss arriving late, after years of growth are already banked and fewer withdrawal years remain. The deterministic projection uses a steady retirement return, but the built-in Monte Carlo overlay scatters good and bad years at random, so its success probability captures the unlucky early-loss paths the smooth line hides.
What is the Monte Carlo simulation and the probability of success?
Rather than assume one tidy average return, the Monte Carlo overlay replays your whole plan across a thousand random market paths, drawing each year's return from a spread set by the volatility you choose. The success probability is the share of those simulated lifetimes whose money funds the plan all the way through your plan-through age; a separate goal probability is the share whose nest egg reaches the target by your retirement age. The fan chart then shows the 10th-to-90th-percentile range and the median path. A fixed random seed keeps the figure stable between runs, and at zero volatility every path collapses back onto the deterministic projection. Treat a result in the high 80s or 90s as healthy, and a lower one as a prompt to save more, spend less, or work a little longer.
What is Fat FIRE, and how does it differ from Lean and Barista FIRE?
Fat FIRE is financial independence funded for a deliberately generous lifestyle rather than a frugal one. Where Lean FIRE multiplies your spending by a fraction below one and Barista FIRE leans on part-time earnings to shrink the pot, Fat FIRE multiplies your income goal upward, by a factor you set such as two or three times, before dividing by your withdrawal rate. The result is a much larger target that buys more travel, housing, healthcare headroom, and slack. All five numbers, Lean, Barista, Coast, full FIRE and Fat, are quoted in today's dollars so you can read them as a single ladder from the lean and early to the rich and unhurried.
How does the optional retirement tax work?
Switch it on and you enter an effective tax rate on the money you draw from your portfolio. Because the income goal you typed is what you want to spend after tax, and a tax-deferred account such as a traditional 401(k) or IRA is taxed on withdrawal, the tool grosses your withdrawals up by one divided by one minus the rate. That larger gross withdrawal raises the target portfolio, the drawdown, and lowers the after-tax income your savings can support. The FIRE tiles stay pre-tax so they keep their familiar 25-times-spending meaning. Leave it off, the default, and nothing changes; the feature is best suited to pre-tax balances, not Roth or already-taxed money.
Can I include a one-time contribution like a bonus or inheritance?
Yes. Set a one-time amount and the age you expect to invest it, and the engine injects that lump sum into your savings at that point, compounding it for the years that remain until retirement. A windfall invested early does far more work than the same sum added near the finish line, so the timing matters; the contribution breakdown lists it as its own line, separate from your regular saving and any employer money. It also feeds the target solver, so the extra capital is reflected in the contribution, return, or retirement age the plan still needs to hit your goal.