Fire Calculator 

FIRE stands for Financial Independence, Retire Early, and this calculator answers its two central questions: how much you need invested before work becomes optional, and how long your current savings path takes to get there. Enter your age, annual spending, savings and expected return to get your FIRE number, years to independence, FI age and progress, plus a year-by-year build-up table and a 40-year retirement drawdown test.

Quick Answer

How to use the FIRE calculator

Fill in your current position (age, savings, yearly savings) and your retirement assumptions (spending, return, inflation, withdrawal rate), then read the headline result and the two tables under it. The optional fields genuinely change the answer, so the order below follows the math.

1. Spending sets the target. Your FIRE number is your retirement spending, grossed up for retirement tax if you set a rate, minus post-retirement income, divided by the withdrawal rate. Nothing else enters that division.
2. Return and inflation combine into one real return. The tool computes (1 + return) ÷ (1 + inflation) − 1 and projects everything in today’s dollars. Enter a nominal return with a realistic inflation figure, or set inflation to 0 and enter a real return directly.
3. The projection walks year by year. Each year the balance grows by the real return, then your annual savings land at year end. The first year the balance reaches the FIRE number is your FI year; the tool reports the count, the FI age, and your progress as a percentage of the number (capped at 100%).
4. The target age solver runs backwards. With a target FI age set, the tool solves for the level yearly savings that lands exactly on the FIRE number in the years available, and reports it per year and per month.
5. The drawdown table then spends it. Starting from the balance you actually reach (which overshoots the number slightly, because savings land in whole years), the tool withdraws your spending need each year for 40 years and reports whether the portfolio survives or the age at which it is depleted.

If you are also working toward nearer milestones, a general financial goal calculator handles the same save-toward-a-target math without the retirement machinery.

The FIRE formulas, exactly as the tool computes them

Five formulas produce every number here. All money figures in the results are rounded to whole dollars, and all projections run in real (today’s-dollar) terms.

Worked example: the pre-filled case, checked year by year

Age 30, $40,000 spending, $50,000 saved, $30,000 saved per year, 5% return, 0% inflation, 4% withdrawal rate, target age 45. Every figure below was reproduced from this tool’s output tables.

Check	Tool output
FIRE number ($40,000 ÷ 0.04)	$1,000,000
Year 1 end balance ($50,000 × 1.05 + $30,000)	$82,500
Year 2 end balance	$116,625
Balance on reaching FI in year 19 (age 49)	$1,042,518
Years to FI / FI age / progress / still need	19 / about 49 / 5.0% / $950,000
Savings required for FI by 45	$41,525/yr ($3,460/mo)
Drawdown verdict at 4%	Survives the full 40-year window, ending near $2,507,321

Two details in that table teach most of what FIRE math involves. The balance overshoots the $1,000,000 target to $1,042,518 because contributions arrive once a year, not continuously, and the drawdown test starts from the overshoot, which is the honest starting point. And the drawdown grows after retirement in this scenario because a 5% real return on roughly $1 million ($52,126 in year one) exceeds the $40,000 withdrawal: a portfolio only shrinks in drawdown when withdrawals outrun growth, which is exactly the failure case the table exists to expose.

Choosing a withdrawal rate: what each option does to the same plan

The withdrawal rate is the one assumption that rescales the target itself. Holding the worked example fixed ($40,000 spending, $50,000 saved, $30,000/yr, 5% real return), the four rates in the selector produce four different retirements:

Withdrawal rate	FIRE number	Years to FI	FI age
3.0% (conservative)	$1,333,333	23	53
3.5% (cautious)	$1,142,857	21	51
4.0% (classic rule)	$1,000,000	19	49
4.5% (aggressive)	$888,889	17	47

Moving from 4% to 3% buys insurance against a long retirement and bad early markets, and the price is concrete: four extra working years on this plan. Moving to 4.5% buys two years back and spends that insurance. Neither is the correct answer in the abstract; the right rate depends on your horizon, which is the subject of the next section. Watching a balance compound is easier with the compound interest doubling time figures in mind: at a 5% real return money doubles roughly every 14 years, which is why the last years of the climb move so much faster than the first.

The 4% rule, honestly: a 30-year answer to a 50-year question

The 4% default comes from William Bengen’s 1994 study of historical US returns, which found that withdrawing 4% of a balanced portfolio in year one, then adjusting the dollar amount for inflation, survived every 30-year period in his data. The 1998 Trinity study by Cooley, Hubbard and Walz confirmed similar success rates across stock and bond mixes.

Three limits of that research matter for FIRE readers specifically. First, the horizon: the studies tested 30 years, while someone retiring at 45 may need 50. A rate that survived 30 years can still fail at 50, which is why this selector includes 3% and 3.5% rather than treating 4% as a floor. Second, the data: both studies rest on US market history, an unusually kind dataset. Third, rigidity: the rule assumes spending never adapts, while real retirees cut back after bad years, and that flexibility supports a higher effective rate than any fixed number. Later reassessments, including Morningstar’s State of Retirement Income research, land in the same place: treat 4% as a researched starting point for a 30-year plan, shade lower for longer horizons, and revisit the plan as markets and spending change. The tool’s own result note says the same thing in one line: the rule is a planning shorthand from Bengen (1994), not a guarantee.

Inflation, post-retirement income and retirement tax: the three inputs most FIRE tools omit

Each of the three optional inputs corrects a specific way the simple version of this math misleads. All three examples below are this tool’s own outputs on the worked example.

Post-retirement income deserves one caution: only count income that will actually be there when you retire, at the amount you enter, in today’s dollars. A pension that starts at 65 does not fund spending at 48, and Social Security claimed at 62 is permanently reduced compared with waiting, per the Social Security Administration’s benefit reduction tables: a worker whose full retirement age is 67 gives up 30% by claiming at 62. Enter the figure you realistically expect to receive, not the largest figure a statement projects.

Reading the two projection tables without fooling yourself

The accumulation table is the plan; the drawdown table is the stress test. Read them in that order, and read the verdict line under the drawdown table before admiring any end balance.

The accumulation table shows one row per year: start balance, growth plus savings, end balance. It stops at the year you cross your FIRE number, and it displays at most 60 rows even when the headline count runs longer (a growth-only plan that takes 62 years shows 60 rows, while the result line still reports 62). The drawdown table then runs a fixed 40 years from your FI age, withdrawing the same real spending need each year. Two behaviors surprise first-time readers. The drawdown starts from the balance you actually reached, overshoot included, not from the round FIRE number. And a portfolio can keep growing through drawdown whenever the real return on the balance exceeds the withdrawal, as in the worked example; depletion, when it happens, is announced in red with the age it occurs. In a deliberately harsh run (age 30, $40,000 spending, 0% return, $30,000/yr saved), starting from $0 saved, the tool reaches FI at 64 and reports depletion around age 90, which is the kind of answer a single FIRE number alone would never give you.

Retiring before 59½: the access problem the FIRE number does not solve

A $1,000,000 portfolio at age 49 is only useful if you can spend from it. Money inside US retirement accounts is generally locked behind a 10% additional tax on distributions before age 59½, on top of ordinary income tax.

Two established bridges exist, and both are rule-bound. The IRS page on substantially equal periodic payments describes the Section 72(t) route: a schedule of withdrawals computed under an IRS-approved method, continued for the longer of five years or until age 59½, avoids the 10% tax; breaking the schedule retroactively triggers it, with interest, under the rules in IRS Notice 2022-6. Separately, many employer plans allow penalty-free withdrawals when you leave the job in or after the year you turn 55. Most early retirees also keep a taxable brokerage bridge fund for the first years, and drawdown from workplace plans has its own wrinkles, covered by the 403(b) withdrawal calculator for that plan type. None of this changes your FIRE number; it changes which dollars you spend in which years, and it is worth modelling before you hand in notice, ideally with the investments you actually hold, such as those priced by an ETF investment calculator.

What competing FIRE calculators miss

The FIRE keyword has strong rivals, and most of them answer a narrower question than the one this page answers.

• Savings-rate calculators (the WalletBurst genre, and Points Frog’s recent entry): elegant proof that the savings rate, not income, sets the timeline, usually from a zero start. They rarely model an existing portfolio plus a target age, and none of the ones tested gross up spending for retirement tax or test a 40-year drawdown.
• Coast FIRE calculators: answer when you can stop saving, a genuinely useful milestone, but they stop at the coast number and never test whether the eventual portfolio survives retirement itself.
• Finmatrix and CalcNova: fast, clean FIRE number and years-to-FI tools with the 25× framing. The method notes are thin, inflation handling is a toggle or an input with no conversion shown, and there is no post-retirement income or tax treatment.
• Vextor Capital: the broadest free rival, with all five FIRE variants and a projection. Variants are preset spending multipliers, though; your own tax rate and continuing income still have nowhere to go.
• Richify: polished what-if scenarios, gated behind connecting real accounts. The generic version is a funnel; the personalised version costs you your financial data.
• Smart FIRE: the one rival that models market crashes instead of a constant return, and says so proudly. It is the more honest risk model, and the heavier lift: account-based, spend-down to life expectancy, and no simple FIRE number headline to compare plans with.
• The gap this page fills: the standard FIRE number, years and FI age, plus the three corrections most tools skip (nominal-to-real conversion shown, post-retirement income netted, spending grossed up for retirement tax), a target-age savings solver, and a printed 40-year drawdown with an explicit depletion age.

Honest limits of this calculator

The projection is a straight line through a jagged process. These limits are properties of the tool, stated so you can discount its answers properly.

• Constant return. Real markets deliver the same average in very different orders, and a crash in the first retirement years does more damage than the average suggests (sequence-of-returns risk). The drawdown table cannot show this; it applies one real return every year.
• Long plans print without a warning. The year counter runs up to 100 years, so a plan that reaches FI at age 92, or even 141, is reported in the same tone as one reaching 49. Sanity-check the FI age against your own life expectancy.
• Displayed rows are capped. The accumulation table prints at most 60 rows even when the journey is longer; the headline year count remains correct.
• Progress is capped at 100%. Overshooting your number does not show as more than 100.0%, and the already-FI message reports your savings against the number instead.
• Spending is flat in real terms, fees are absent. Investment fees enter only if you lower the return you type, and real spending that falls in later retirement, or jumps for health care, is not modelled.
• Not financial advice. This calculator is an educational projection, not a retirement plan. Taxes, benefits claiming and withdrawal sequencing for a real early retirement deserve a qualified fiduciary adviser.

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