Audited 26 May 2026·Last updated 27 Jul 2026·8 citations·Tier 1·0 uses

Retirement & FIRE Calculator

Free FIRE calculator. Find your years to financial independence using the 4% safe withdrawal rate, the 25x rule, and real investment returns.

Retirement & FIRE Calculator

Total value of your invested assets today — taxable brokerage, 401(k), IRA, HSA, and any other accounts you can draw from in retirement. Exclude your primary residence equity unless you plan to liquidate it.
$
Your annual take-home pay across all sources — salary net of federal, state, payroll, and local taxes. The calculator uses this together with spending to derive your annual savings.
$
Total annual expenses you expect to maintain in retirement, in today's dollars. Include housing, food, transportation, healthcare, and discretionary. This drives both your savings rate and your target portfolio via the 25x rule.
$
Long-run annualized real return on your portfolio after inflation. Historical US 60/40 portfolios returned roughly 5%–7% real; 100% equities closer to 7%. Use a conservative figure if you are within 10 years of FI.
%
The percentage of your portfolio you plan to withdraw in year one of retirement, then adjust each year for inflation. Bengen's 1994 study and the Trinity Study set this at 4% for a 30-year horizon; longer retirements often use 3.25%–3.5%.
%
Long-run inflation rate. Reserved for future inflation-adjusted spending models. Because the expected return field above is already a real (inflation-adjusted) return, this value does not change the years-to-FI math today.
%
Years to financial independence
10.6
The number of years from today until your invested portfolio reaches the target needed to fund your annual spending at the chosen safe withdrawal rate, given the savings rate and real return implied by your inputs.
FI number (target portfolio)
$1,000,000.00
Monthly savings
$5,000.00
Savings rate
60.00 %
Portfolio value at FI
$1,000,000.00

Background.

A FIRE calculator answers the only retirement-planning question that actually matters in dollar terms: how many years of saving and compounding does it take before your invested portfolio is large enough to fund your lifestyle without a paycheck? FIRE stands for Financial Independence, Retire Early — a movement that traces its modern arithmetic to William Bengen's 1994 Journal of Financial Planning paper 'Determining Withdrawal Rates Using Historical Data,' which established the original 4% safe withdrawal rate, and to the 1998 'Trinity Study' by Cooley, Hubbard, and Walz at Trinity University, which stress-tested that rate against rolling historical periods of US stocks and bonds.

The math the FIRE community uses is unforgiving and simple. Your FI number — the portfolio at which work becomes optional — is your annual spending divided by your safe withdrawal rate. At the canonical 4% SWR this is exactly twenty-five times your annual expenses, which is why FIRE writers refer interchangeably to 'the 4% rule' and 'the 25x rule.' Once you know the target, the timeline collapses to four levers: your current portfolio, your annual savings (income minus spending), your expected real return on investments, and the SWR itself. This calculator runs the same future-value-of-annuity equation that personal finance writers like Mr. Money Mustache and academic researchers like Wade Pfau use, and solves for the unknown — years to FI — using Newton-Raphson iteration because the equation has no closed-form solution.

Enter your current invested assets, your after-tax annual income, your annual spending in today's dollars, the long-run real return you expect on your portfolio after inflation, and the safe withdrawal rate you trust, and you will get back the years to financial independence, your FI number, your monthly savings, your savings rate, and the projected portfolio value at the FI horizon.

The single most important insight from running these numbers is the dominance of savings rate over absolute income. A person earning $80,000 who lives on $32,000 has a 60% savings rate and, at a 7% real return, will reach FI in just under twelve years. A person earning $200,000 who lives on $160,000 has only a 20% savings rate and will need about thirty-five years to reach FI — even though their absolute savings are higher in early years, their FI target is four times larger because they have grown accustomed to a much more expensive lifestyle. This is the core lesson Mr. Money Mustache made famous in his 2012 essay 'The Shockingly Simple Math Behind Early Retirement': the percentage of income you save is more powerful than how much you earn, because saving a higher fraction simultaneously raises the savings stream and lowers the target.

A few honest cautions about the 4% rule that this calculator does not silently paper over. First, the original Trinity Study assumed a 30-year retirement, a 50/50 to 75/25 stock-bond portfolio, and rebalancing annually — extending the horizon to a 50- or 60-year early retirement reduces the historically safe rate to roughly 3.25% to 3.5%, as Pfau, Kitces, and the Early Retirement Now SWR series have shown. Second, the 4% figure was derived from US historical returns from 1926 to 1976 in Bengen's original paper, a period that includes both the Great Depression and the 1970s stagflation — but it does not guarantee future returns will be drawn from the same distribution, particularly in a high-equity-valuation regime.

Third, the safe withdrawal rate is gross of taxes; if your portfolio sits primarily in pre-tax 401(k) or traditional IRA accounts you will owe ordinary income tax on every dollar withdrawn, so your true sustainable spending is lower than the SWR suggests unless you have done substantial Roth conversion work. Fourth, the calculator uses a real (inflation-adjusted) return rather than a nominal return — which means the answer it gives you is in today's purchasing power, and your portfolio value at FI is the value in today's dollars, not the nominal future dollar amount you will see on your brokerage statement. Use it as the right first-pass tool for FI planning, then layer in tax efficiency, sequence-of-returns risk modeling, and your specific retirement-account mix.

What is retirement & fire calculator?

Financial Independence, Retire Early (FIRE) is a personal finance framework in which a saver accumulates enough invested assets that the inflation-adjusted withdrawals from the portfolio cover annual expenses indefinitely, removing the requirement to earn a paycheck. The arithmetic foundation of FIRE is the safe withdrawal rate (SWR) — the percentage of an initial portfolio that can be withdrawn each year, with the withdrawal amount adjusted upward annually for inflation, without depleting the portfolio over the planning horizon. William Bengen's 1994 paper established 4% as the historically safe rate for a 30-year retirement using US stock-bond portfolios, and the 1998 Trinity Study by Cooley, Hubbard, and Walz extended the analysis across rolling 30-year periods and confirmed that 4% (with a 50/50 to 75/25 equity allocation) produced a portfolio-survival rate above 95% in historical data. From that single rate comes the 25x rule: if you can sustainably withdraw 4% of your portfolio per year, then your portfolio must equal 1 / 0.04 = 25 times annual spending. The FI number is therefore annual spending multiplied by 25 (or, equivalently, divided by the SWR expressed as a decimal). FIRE practitioners commonly distinguish several flavors — Lean FIRE (a frugal target around $25,000 to $40,000 in annual spending), Regular FIRE (median US household spending of $50,000 to $75,000), Fat FIRE (a comfortable target of $100,000 or more), and Coast FIRE (the point at which your existing portfolio will grow to your full FI number without further contributions, even if you stop saving today). All of them rest on the same mathematics this calculator implements.

How to use this calculator.

  1. Enter your current portfolio value. Include every invested account you can eventually draw from in retirement — taxable brokerage, 401(k), 403(b), IRA, Roth IRA, HSA used as an investment account, and any after-tax investments. Exclude your primary residence equity unless you genuinely plan to sell and downsize.
  2. Enter your after-tax annual income. This is your total take-home pay across all sources — net of federal, state, payroll, and local taxes. Do not enter gross salary; the calculator works in spendable dollars so that income minus spending equals real savings.
  3. Enter your annual spending in today's dollars. Be honest. Pull twelve months of bank and credit card statements and total them, including the irregular bills (insurance, property taxes, car maintenance, holidays). Spending is the single most powerful lever in the model because it simultaneously raises required savings and lowers the FI target.
  4. Enter your expected real return on investments. Use a long-run inflation-adjusted figure — historical US 60/40 portfolios returned roughly 5% real, 100% global equities about 7% real over the last century. Bengen's original 4% rule was derived using these historical real returns. Be conservative if you are within 10 years of your target.
  5. Enter your safe withdrawal rate. The canonical Trinity Study figure is 4%. Modern research from Pfau, Kitces, and the Early Retirement Now SWR series suggests 3.25% to 3.5% for retirement horizons longer than 40 years, and the Vanguard 2022 research note 'Fuel for the FIRE' recommends adjusting downward for very early retirees. Use 4% as a baseline; sensitivity-test with 3.5% if you plan to retire before 45.
  6. Read your years to FI as the primary output and your FI number as the second. Then look at your savings rate — if it is below 25%, the model's timelines will be long no matter what return you assume, and Mr. Money Mustache's 'Shockingly Simple Math' table is worth studying before adjusting any other input.

The formula.

FI = Spending ⁄ (SWR⁄100)
FI · target portfolio (25× rule)Spending · annual spendingSWR · safe withdrawal rate %

The calculation runs in two stages. Stage one is the FI number — your target portfolio. Bengen's safe-withdrawal-rate framework states that a portfolio can sustain inflation-adjusted withdrawals indefinitely (for the planning horizon studied) if those withdrawals equal a fixed percentage SWR of the initial portfolio. Solving for the portfolio gives targetPortfolio = annualSpending / (SWR / 100), which at SWR = 4% simplifies to the famous 25x rule: targetPortfolio = annualSpending × 25. Stage two solves for the time it takes your current portfolio to grow into that target under regular contributions. The standard future-value-of-annuity equation with an initial lump sum is FV = PMT × ((1 + r)^n − 1) / r + PV × (1 + r)^n, where FV is the target portfolio, PMT is annual savings (income minus spending), PV is current portfolio, r is the real annual return as a decimal, and n is years to FI. There is no algebraic solution for n, so the calculator uses Newton-Raphson iteration: define f(n) = PMT/r × ((1+r)^n − 1) + PV × (1+r)^n − FV and its derivative f'(n) = (PMT/r + PV) × ln(1+r) × (1+r)^n, then iterate n_{i+1} = n_i − f(n_i) / f'(n_i) from a starting guess of n = 10 until successive estimates differ by less than 1e-9. The solver converges in under ten iterations for any realistic input set because the function is monotonically increasing in n. When r = 0 the formula degenerates to straight-line accumulation: n = (FV − PV) / PMT. The remaining outputs are derived directly — monthlySavings = (annualIncome − annualSpending) / 12, savingsRatePercent = (annualIncome − annualSpending) / annualIncome × 100, and portfolioAtFI is the future-value equation evaluated at the solved n (which should equal targetPortfolio to within rounding).

A worked example.

Example

Consider a 30-year-old earning $100,000 after tax, living on $40,000, with $50,000 already invested, expecting a 7% real return on a stock-heavy portfolio, and using the canonical 4% safe withdrawal rate. The FI number is $40,000 / 0.04 = $1,000,000 — the classic 25x rule applied to $40,000 of annual spending. Annual savings are $100,000 − $40,000 = $60,000, which is $5,000 per month and a 60% savings rate. Plugging into the future-value-of-annuity equation 60,000 × ((1.07^n − 1) / 0.07) + 50,000 × 1.07^n = 1,000,000 and solving for n with Newton-Raphson gives n ≈ 10.59 years. The portfolio value at that horizon is, by construction, approximately $1,000,000 in today's dollars. The takeaway is the savings rate. Drop spending to $30,000 (a 70% savings rate) and the FI number falls to $750,000, the annual savings rise to $70,000, and the years to FI drop to about 8.0. Conversely, raise spending to $60,000 (a 40% savings rate) and the FI number jumps to $1,500,000, annual savings fall to $40,000, and years to FI extend to roughly 19. This is the central insight Mr. Money Mustache's 2012 'Shockingly Simple Math' essay drilled home: savings rate, not income, dominates the timeline.

annual Return Percent7
annual Income100,000
inflation Percent3
withdrawal Rate Percent4
annual Spending40,000
current Savings50,000

Frequently asked questions.

What is FIRE and how does the FIRE calculator work?
FIRE stands for Financial Independence, Retire Early — a personal finance movement built on the idea that once your invested portfolio is large enough to fund your annual spending at a sustainable withdrawal rate, you no longer need to work for income. The math has two steps. First, compute your FI number — the portfolio value at which work becomes optional — by dividing annual spending by your safe withdrawal rate (at 4%, this is exactly 25 times annual spending, known as the 25x rule). Second, project how many years it takes your current portfolio, plus regular savings, to grow into that target at your expected real return on investments. This calculator implements the standard future-value-of-annuity equation with an initial lump sum, solving for years using Newton-Raphson iteration because the equation has no closed-form solution for n. The output — years to FI — is the time horizon under which your stated savings rate and return assumption deliver you to a work-optional portfolio.
Is the 4% rule still safe in 2026?
It depends entirely on your retirement horizon and asset allocation. Bengen's original 1994 paper and the 1998 Trinity Study established 4% as historically safe for a 30-year US retirement with a 50/50 to 75/25 stock-bond allocation — and within that window, the rule still survives stress testing in current research. For early retirees facing 40- to 60-year horizons, however, modern work by Wade Pfau, Michael Kitces, and the Early Retirement Now SWR series shows the historically safe rate drops to roughly 3.25% to 3.5%. Vanguard's 2022 research note 'Fuel for the FIRE: Updating the 4% Rule for Early Retirees' explicitly recommends a 3.3% baseline for retirees with horizons over 50 years. Current US equity valuations (Shiller CAPE) are also elevated relative to the historical sample Bengen used, which several researchers argue further reduces the prudent SWR. A reasonable approach for 2026: use 4% as a planning baseline if you are retiring at a traditional age with a 30-year horizon, and 3.5% if you are pursuing early FIRE with a 40-year-plus horizon.
What is the difference between nominal return and real return, and which one should I enter?
Nominal return is the headline growth rate of your portfolio in raw dollars — historically around 10% for the S&P 500 since 1926. Real return is nominal return minus inflation — historically around 7% for US equities. This calculator uses real return because the FI number is denominated in today's dollars (annual spending today), and using a nominal return against a real spending target would give you a misleadingly fast timeline. If your portfolio grows 10% but inflation runs 3%, your purchasing power only grew 7% — and 7% is the figure that connects today's spending to tomorrow's affordability. Always enter the inflation-adjusted real return. For a typical balanced portfolio assume 5%–6% real; for 100% global equities assume 6%–7% real; for a conservative bond-heavy retirement portfolio assume 2%–3% real. When in doubt, use 5% as a defensible long-run real return assumption.
Does this calculator account for taxes on retirement withdrawals?
No, and this is one of the most important limits of the simple FIRE math. The 4% safe withdrawal rate is computed gross of taxes — it tells you that 4% of your portfolio per year can be withdrawn, but it does not tell you that 4% of the post-tax cash will land in your spending account. If your portfolio sits primarily in pre-tax 401(k) or traditional IRA accounts, every withdrawal is taxed as ordinary income, so a $40,000 gross withdrawal might net only $32,000 to $36,000 depending on your tax bracket and state. To plan accurately, either set your annual spending input to a gross figure (spending plus expected taxes on withdrawals), or do substantial Roth conversion work during your accumulation years so that more of the portfolio is in tax-free accounts. Many FIRE practitioners use a Roth conversion ladder — converting traditional IRA to Roth IRA in low-income early retirement years — to manage the tax problem. Healthcare costs and ACA premium subsidies are similarly absent from this model and matter materially for retirees under 65.
Can I include Social Security or a pension in the FIRE calculation?
Not in this calculator directly, but you can model their effect by subtracting their inflation-adjusted annual benefit from your annual spending input. If you expect $24,000 per year in Social Security starting at age 67 and you spend $50,000 today, your effective post-Social-Security spending need from the portfolio is $26,000 — which dramatically reduces your FI number. The mechanical adjustment is rough because Social Security does not start the day you achieve FI, so you may need a larger portfolio to bridge from FIRE age to Social Security age, then can withdraw less from the portfolio thereafter. Tools like Big ERN's Safe Withdrawal Rate Series spreadsheet model these multi-stage cash flows explicitly. For a first-pass calculation, the bridge-then-supplemented approach (subtract expected guaranteed income from spending to get your portfolio-funded need) is a reasonable simplification.
Why does the savings rate matter so much more than the income level?
Because savings rate is the single number that simultaneously raises your annual contribution and lowers your FI target. A higher savings rate means you save more per year (numerator grows) and that you live on less per year (denominator of the FI target shrinks). Mr. Money Mustache's 2012 essay 'The Shockingly Simple Math Behind Early Retirement' worked out the table: a 10% savings rate takes about 51 years to FI; 25% takes 32 years; 50% takes 17 years; 65% takes 10.5 years; 75% takes about 7 years; 80% takes 5.5 years; 90% takes 3 years. These figures assume a 5% real return and a 4% SWR. The numbers are mechanical and they do not depend on absolute income. A doctor earning $400,000 who spends $350,000 has a 12.5% savings rate and a 40-year path to FI; a teacher earning $60,000 who spends $30,000 has a 50% savings rate and a 17-year path. Income matters because it sets the ceiling on possible savings rate, but the discipline of spending sets the actual timeline.
What are Lean FIRE, Regular FIRE, Fat FIRE, and Coast FIRE?
These are colloquial categories the FIRE community uses to describe different spending and accumulation targets. Lean FIRE describes a frugal retirement at roughly $25,000 to $40,000 of annual spending — typically requires a $625,000 to $1,000,000 portfolio at 4% SWR and aggressive expense management. Regular FIRE targets median US household spending of $50,000 to $75,000 — a $1.25M to $1.875M portfolio. Fat FIRE describes a comfortable upper-middle-class retirement at $100,000-plus of annual spending — a $2.5M-plus portfolio, often with a paid-off home in addition. Coast FIRE is a different concept: the point at which your existing portfolio will grow to your full FI number through compounding alone, with no further contributions, by some target retirement age — usually traditional retirement age 60 or 65. A 30-year-old with $200,000 invested at 7% real return will reach $1.6M by age 60 with zero additional contributions, so if their FI number is $1.6M they are already Coast FI. Each variant uses the same calculator; only the spending input changes.
How is the FIRE calculation different from the standard retirement calculator I see on bank websites?
Three differences. First, the FIRE framework uses a safe withdrawal rate to derive the portfolio target rather than a fixed age-65 retirement assumption — which means the calculator works equally well for someone planning to retire at 35 or 75. Second, the FIRE math runs in real (inflation-adjusted) dollars throughout, so your spending today maps directly to your portfolio target today; standard retirement calculators usually inflate future spending and project nominal portfolio values, which is harder to reason about intuitively. Third, the FIRE framework treats savings rate as the primary lever and assumes the saver is willing to adjust spending to accelerate FI — whereas bank retirement calculators typically assume fixed spending growth and a fixed retirement age, then solve for required contributions. The Trinity Study, Bengen 1994, and the broader academic SWR literature on which FIRE is built are the same body of research professional financial planners use; FIRE just applies it more aggressively to early retirement horizons.
What is sequence-of-returns risk and does the FIRE calculator account for it?
Sequence-of-returns risk is the danger that a string of poor portfolio returns early in retirement permanently impairs the portfolio's ability to sustain withdrawals — even if the long-run average return matches expectations. A retiree who experiences a 30% drawdown in year one and continues withdrawing 4% of the original portfolio is selling shares at depressed prices, which mathematically prevents the portfolio from ever recovering to its baseline trajectory. This risk is the core reason the Trinity Study examined every rolling 30-year window in US history rather than just the average return — because the order of returns matters, not just the average. This calculator does not model sequence risk because it assumes a single deterministic real-return rate, which is appropriate for the accumulation phase (when sequence risk is small) but understates risk in early withdrawal years. For decumulation-phase planning, use Monte Carlo simulators (FIRECalc, cFIREsim, Portfolio Visualizer, or Big ERN's spreadsheet) which apply historical or simulated return sequences to test portfolio survival rates.
What real return should I assume for a US stock-bond portfolio in 2026?
Long-run historical data from Robert Shiller, Dimson-Marsh-Staunton (Credit Suisse Global Investment Returns Yearbook), and Jeremy Siegel's Stocks for the Long Run gives the following ballpark real returns for the post-1900 era: US large-cap equities about 6.5%–7% real, global equities about 5%–5.5% real, US bonds about 2% real, US T-bills about 0.5% real. For a 60/40 US stock-bond portfolio rebalanced annually, the historical real return is roughly 5% to 5.5%. For 100% global equities, roughly 5.5% to 6.5% real. Current forward-looking estimates from Vanguard, Research Affiliates, and AQR for the 2025–2035 decade are lower than the historical average — typically 4%–5% real for global equities and 1.5%–2.5% real for bonds — because US equity valuations (Shiller CAPE near 35 in late 2025) are elevated relative to history. A defensible 2026 planning assumption: 5% real for a balanced portfolio, 6% for stock-heavy, 4% for bond-heavy. Run the calculator with a sensitivity analysis at plus and minus 1% to see how brittle your timeline is to the return assumption.

References& sources.

  1. [1]Bengen, W. P. (1994). 'Determining Withdrawal Rates Using Historical Data.' Journal of Financial Planning, October 1994 — the original 4% safe withdrawal rate paper.
  2. [2]Cooley, P. L., Hubbard, C. M., & Walz, D. T. (1998). 'Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable.' AAII Journal — the 'Trinity Study' establishing portfolio-survival rates across historical 30-year windows.
  3. [3]Pfau, W. D. (2011). 'Safe Savings Rates: A New Approach to Retirement Planning Over the Life Cycle.' Journal of Financial Planning, May 2011.
  4. [4]Karsten Jeske (Big ERN) — 'Safe Withdrawal Rate Series.' Early Retirement Now — the most comprehensive open-source SWR analysis for early retirees with horizons beyond 30 years.
  5. [5]Vanguard Research (2022). 'Fuel for the FIRE: Updating the 4% Rule for Early Retirees.' Vanguard Investment Strategy Group white paper.
  6. [6]Adeney, P. ('Mr. Money Mustache') (2012). 'The Shockingly Simple Math Behind Early Retirement.' mrmoneymustache.com — the canonical popular essay establishing savings-rate-to-years-to-FI table.
  7. [7]Kitces, M. (2018). 'The Extraordinary Upside Potential Of Sequence Of Return Risk In Retirement.' Nerd's Eye View — sequence-of-returns risk and the 4% rule.
  8. [8]Siegel, J. J. (2014). Stocks for the Long Run, 5th edition. McGraw-Hill — long-run real returns of US equities, bonds, and T-bills.
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