Enter your savings, withdrawal rate, and expected return to find out exactly how long your nest egg will last — or if it will last forever.
Your money will last
Your return rate covers your withdrawals — your balance grows indefinitely.
| Year | Start Balance | Withdrawn | Interest | End Balance |
|---|---|---|---|---|
| 1 | €500,000 | €24,000 | €25,023 | €501,023 |
| 2 | €501,023 | €24,000 | €25,076 | €502,099 |
| 3 | €502,099 | €24,000 | €25,131 | €503,229 |
| 4 | €503,229 | €24,000 | €25,188 | €504,418 |
| 5 | €504,418 | €24,000 | €25,249 | €505,667 |
| 6 | €505,667 | €24,000 | €25,313 | €506,980 |
| 7 | €506,980 | €24,000 | €25,380 | €508,361 |
| 8 | €508,361 | €24,000 | €25,451 | €509,812 |
| 9 | €509,812 | €24,000 | €25,525 | €511,337 |
| 10 | €511,337 | €24,000 | €25,603 | €512,940 |
| 11 | €512,940 | €24,000 | €25,685 | €514,625 |
| 12 | €514,625 | €24,000 | €25,772 | €516,397 |
| 13 | €516,397 | €24,000 | €25,862 | €518,259 |
| 14 | €518,259 | €24,000 | €25,957 | €520,217 |
| 15 | €520,217 | €24,000 | €26,058 | €522,274 |
| 16 | €522,274 | €24,000 | €26,163 | €524,437 |
| 17 | €524,437 | €24,000 | €26,273 | €526,710 |
| 18 | €526,710 | €24,000 | €26,390 | €529,100 |
| 19 | €529,100 | €24,000 | €26,512 | €531,612 |
| 20 | €531,612 | €24,000 | €26,641 | €534,253 |
The money longevity calculator answers the most critical question in retirement planning: given how much I have saved and how much I plan to spend each year, how long will my money last? Unlike savings growth calculators that project future balances, this tool runs in reverse — starting from a lump sum and simulating how many years of withdrawals it can sustain at a given investment return rate.
The calculation is straightforward in concept but profoundly important in practice. A retiree with $800,000 withdrawing $50,000/year at a 5% portfolio return will run out of money in roughly 27 years. If that same retiree reduces withdrawals to $40,000/year (a modest lifestyle adjustment), the money lasts indefinitely — the investment return covers all withdrawals. This tipping point, where return equals withdrawal, is the boundary between a sustainable and an unsustainable retirement plan.
The single greatest risk in retirement is longevity risk — the possibility of outliving your savings. Americans who reach age 65 have a 50% chance of living to 85 and a meaningful chance of reaching 90 or beyond. Planning for only 20 years of retirement when you live for 30 means running out of money precisely when you are most vulnerable and least able to return to work. The money longevity calculator forces this math into the open so you can plan accordingly.
This calculator is also valuable for non-retirement scenarios: modeling how long a severance payment will last during a job search, projecting how many years a college fund will cover tuition, or understanding how long an inheritance can supplement income. Any situation involving a lump sum being drawn down over time — with or without investment returns — can be analyzed with this tool.
Historically, formal longevity analysis emerged from actuarial science in the life insurance and pension industries. Life insurers, pension fund managers, and defined-benefit plan administrators have applied present-value annuity mathematics since the late 19th century to ensure promised payments remain funded over the lifetime of beneficiaries. Endowment managers at universities and foundations use identical frameworks — typically a 4–5% annual distribution policy from the trailing 12-quarter average portfolio value — to balance current spending needs with perpetual corpus preservation. The same principles that govern a multi-billion-dollar university endowment scale directly to a personal retirement portfolio without modification.
Structured settlement planners, disability insurance underwriters, and trust attorneys all commission longevity analyses as a routine part of their professional work. Courts use present-value annuity calculations when awarding lump-sum personal injury damages that must fund decades of future medical care. Understanding that these rigorous professional contexts apply the same underlying formula reinforces that the money longevity calculator is not a simplified approximation — it is the genuine tool of institutional finance adapted for personal use.
The calculator simulates each year of the withdrawal period: it credits investment return on the starting balance, then deducts the annual withdrawal, and records the remaining balance. This repeats year by year until the balance reaches zero. The year in which the balance is depleted is your money's longevity under those assumptions.
PV — Present Value (Starting Balance)
The principal being drawn down. The larger PV is relative to annual withdrawal, the longer money lasts. Each additional dollar of PV generates ongoing investment returns that continuously extend the drawdown timeline.
PMT — Annual Withdrawal Amount
Your annual spending from the portfolio. This is the single most controllable variable in longevity planning. Even a 10% reduction in PMT can add 3–7 years to a portfolio's life by simultaneously reducing cash drain and leaving more capital earning returns.
r — Annual Rate of Return
The portfolio return credited each year during the withdrawal phase. A balanced 60/40 portfolio has historically returned 5–7% annually. Use conservative estimates (4–5%) for planning to avoid overoptimism — actual returns vary significantly year to year.
n — Years Money Lasts (Output)
The result of the longevity calculation. When PV × r ≥ PMT, n is infinite — the portfolio is self-sustaining. When PV × r < PMT, n is finite and calculated using the logarithmic annuity formula. The breakeven point is when return exactly equals withdrawal.
Starting Portfolio Balance: The total value of savings and investments you will draw from.
Annual Withdrawal Amount: Your planned annual spending from the portfolio (total expenses minus any guaranteed income like Social Security).
Expected Annual Return: The realistic average annual return on your portfolio during the withdrawal period.
Inflation Rate (optional): If selected, the withdrawal amount grows annually by this percentage to model real purchasing power maintenance.
Years Until Depletion: The number of years the portfolio will last at the specified withdrawal rate and return.
Depletion Year: The estimated calendar year in which funds run out.
Year-by-Year Balance Chart: A visualization showing the portfolio balance declining over time until depletion.
Sustainability Status: Whether the withdrawal rate is sustainable indefinitely (return covers withdrawals) or will eventually deplete the portfolio.
The closed-form solution for how long a portfolio lasts derives from the present value of an annuity formula, solved for n. When the annual return times the portfolio balance exceeds the withdrawal, the portfolio is sustainable indefinitely. Below that threshold, the formula gives the finite lifespan.
n = -ln[1 - (PV × r) / PMT] / ln(1 + r)
n = years money lasts | PV = starting balance | r = annual return rate | PMT = annual withdrawal | Requires PMT > PV × r
Inputs: Portfolio = $900,000 | Annual withdrawal = $48,000 | Annual return = 6%
Step 1: Check if sustainable: PV × r = $900,000 × 0.06 = $54,000 > $48,000 withdrawal. Portfolio is sustainable indefinitely — return exceeds withdrawals by $6,000/year and the portfolio actually grows.
Alternative inputs: Portfolio = $700,000 | Annual withdrawal = $48,000 | Return = 6%
Step 2: PV × r = $700,000 × 0.06 = $42,000 < $48,000. Portfolio will deplete. Apply formula.
Result: n = -ln[1 - ($700,000 × 0.06) / $48,000] / ln(1.06) = -ln[1 - 0.875] / 0.05827 = -ln(0.125) / 0.05827 = 2.079 / 0.05827 ≈ 35.7 years.
Scenario: Helen retires at 70 with $650,000 in a conservative 40/60 stock-bond portfolio earning 4.5%/year. She receives $26,400/year in Social Security and needs $55,000/year in total spending. Portfolio withdrawal required: $55,000 − $26,400 = $28,600/year.
Sustainability check: PV × r = $650,000 × 0.045 = $29,250 > $28,600. The portfolio is just barely self-sustaining — Helen's investment return exceeds her portfolio withdrawal by $650/year, so the balance grows slowly in nominal terms.
Inflation scenario: If Helen increases withdrawals by 3% annually for purchasing power, the withdrawal rises above returns by year 4. Re-running with inflation-adjusted withdrawals: n ≈ 28 years — funds last to age 98, an excellent outcome.
Key insight: Delaying Social Security to age 70 (versus 62) gave Helen 76% more annual income, transforming what would have been a rapidly depleting portfolio at age 62 into a near-perpetual one at 70. The timing of guaranteed income is as important as portfolio size.
Running out of money in retirement is the financial equivalent of a worst-case scenario — and unlike younger life stages, there is limited ability to recover by returning to full-time work. The money longevity calculator gives you the information to prevent this outcome while you still have time to accumulate more savings, reduce planned spending, or delay retirement. Knowing the number forces the planning that protects your future self.
The 4% rule — withdraw 4% of your initial portfolio annually, adjusted for inflation — has become a widely used heuristic precisely because the money longevity calculation shows it is historically sustainable over 30-year periods for balanced portfolios. But the 4% rule was derived from historical U.S. data and may be too aggressive for current conditions of high valuations and potentially lower future returns. Running the longevity calculation with conservative return assumptions (4–5%) provides a more robust plan than relying on historical averages.
Longevity planning also reveals the enormous value of guaranteed income streams. Social Security, a pension, or an annuity provides income that cannot be outlived — reducing the portfolio withdrawal required and dramatically improving longevity. A retiree with $25,000/year in Social Security who needs $50,000/year only needs their portfolio to cover $25,000 — cutting the required nest egg (at the 4% rule) from $1,250,000 to $625,000. Maximizing Social Security through delayed claiming is one of the highest-return decisions most retirees can make.
The money longevity calculator is also a communication tool for couples, families, and financial advisors. It makes the stakes of retirement funding concrete and emotionally accessible in a way that abstract balance sheet numbers cannot. Seeing a chart where the portfolio hits zero in year 22 — when you might be 87 — focuses attention on the right questions: Can we spend less? Should we delay retirement? Is there a part-time income stream we can maintain?
Professional financial planners, estate attorneys, and institutional fund managers all rely on variants of longevity modeling. Defined-benefit pension fund actuaries run longevity analyses quarterly to confirm plan solvency. University endowment committees set annual distribution policies using the same sustainable withdrawal logic applied to multi-billion-dollar portfolios. Understanding that these institutions apply identical principles at scale validates the rigor of applying the same analysis to a personal retirement portfolio.
Misinterpretations of longevity projections are common and worth addressing. The most frequent error is treating a fixed-return model as a guarantee — it is a deterministic approximation, not a promise. Actual market returns are volatile and sequence-dependent; a 6% average return model that shows 35 years of longevity may fail in year 20 if early returns are significantly negative. Equally common is conflating nominal and real returns: a 7% nominal return with 3% inflation is only a 4% real return, and using nominal figures without inflation-adjusting withdrawals systematically overstates portfolio longevity. A well-run longevity analysis clearly distinguishes nominal from real figures and stress-tests against at least one pessimistic scenario.
Couples face a compounded longevity challenge: the plan must fund two lifetimes, and the surviving spouse will continue withdrawing from the portfolio after the first death — often with higher healthcare costs and potentially reduced income if one Social Security benefit ceases. Joint longevity planning should model the survivor scenario explicitly: what does the portfolio look like if one spouse passes at age 78 while the other lives to 92? Survivor income, reduced household expenses, and the single-filer tax rate all shift the calculation meaningfully. Running both scenarios ensures the surviving partner is not left in financial jeopardy.
For those who inherit wealth or receive a settlement, the money longevity calculator answers a slightly different version of the same question: given a lump sum I did not plan to have, how long can I stretch it while investing it conservatively? An inheritance of $400,000 deposited in a balanced portfolio at 5% return and drawn at $25,000/year provides roughly 30 years of supplemental income — a meaningful planning horizon that allows the recipient to decide whether to invest the money for growth, use it for income, or blend both approaches.
These scenarios illustrate how small changes in withdrawal rate or return dramatically affect retirement money longevity.
Maria and James, both 65, have $850,000 saved. They plan to spend $60,000/year and expect a 6% portfolio return. Longevity calculation: n = -ln[1 - ($850,000 × 0.06) / $60,000] / ln(1.06) = -ln[1 - 0.85] / 0.05827 = -ln(0.15) / 0.05827 = 1.897 / 0.05827 ≈ 32.6 years. Their money lasts to age 97 — an excellent outcome. If they had planned $70,000/year instead, it would last only 21 years (to age 86), dangerously close to average life expectancy. The $10,000 annual spending difference means 11 extra years of financial security.
Alex retires at 50 with $1,200,000, plans to withdraw $45,000/year (3.75% rate), and expects 7% real returns. At 3.75% withdrawal rate with 7% return, the portfolio is sustainable indefinitely: $1,200,000 × 7% = $84,000 > $45,000 withdrawal. The portfolio actually grows in real terms. If Alex had chosen $90,000/year (7.5% withdrawal rate), the money would last only about 20 years — running out at age 70, precisely when healthcare costs peak. The 3.75% discipline is what makes a 40-year early retirement financially viable.
Sandra receives a $180,000 severance package and plans to live on $4,500/month ($54,000/year) while searching for a new role. She invests in a money market account at 4.8% APY. How long does it last? n = -ln[1 - ($180,000 × 0.004) / $4,500] / ln(1.004) = -ln[1 - 0.16] / 0.003992 = -ln(0.84) / 0.003992 = 0.1744 / 0.003992 ≈ 43.7 months — nearly 4 years. If Sandra reduces spending to $3,500/month, it lasts over 7 years. The calculator helps her understand how long she can take to find the right role without financial panic.
Using average return instead of planning for downturns
A 7% average return does not mean 7% every year — markets can drop 30–40% in a single year. Using the average in a longevity calculator produces an overly optimistic result. Run the calculation at 4–5% to stress-test your plan. The gap between the 7% and 4% results is your margin of safety.
Ignoring inflation on withdrawals
Fixed $50,000 annual withdrawals sound manageable, but at 3% inflation, that $50,000 has the purchasing power of only $27,684 after 20 years. Model inflation-adjusted spending to see how much faster purchasing power erodes and plan accordingly — typically requiring either more savings or lower initial withdrawals.
Not counting Social Security and pension income
Many retirees model their portfolio in isolation, forgetting to subtract guaranteed income from the withdrawal requirement. If you receive $24,000/year in Social Security, subtract that before entering the withdrawal amount. This single adjustment can dramatically improve the longevity projection and may reveal that your portfolio is more than sufficient.
Planning to average life expectancy instead of beyond it
Planning to age 83 (average life expectancy for a 65-year-old man) means a 50% probability of outliving your funds. Plan to 90–95 to have high confidence in financial security regardless of longevity. The extra years cost you little in current savings but protect against a devastating outcome.
Holding too much cash in retirement
Retirees sometimes shift entirely to cash or CDs out of fear, earning 4–5% while inflation runs at 3–4%. The net real return of 0–2% may be insufficient to sustain 30-year retirements. A meaningful equity allocation (40–50%) in a balanced portfolio provides the long-term growth needed to outpace withdrawals over multi-decade retirements.
Failing to model healthcare cost spikes
A single major illness, long-term care need, or dental procedure can cost $50,000–$200,000+ and dramatically accelerate portfolio depletion. Model at least one large healthcare expense in your retirement plan and maintain a separate healthcare reserve (HSA, supplemental insurance) to prevent it from derailing your core retirement portfolio.
Not revisiting the calculation annually
Markets move, spending changes, and rates shift. A retirement plan accurate today may be significantly off in 3 years. Re-run the money longevity calculator every year using your actual current portfolio balance and real spending. This annual check-in allows early intervention if the plan drifts off track — before small adjustments become large crises.
This benchmark table shows approximate portfolio longevity for common withdrawal rates across three return scenarios. Use it for rapid orientation before running the full calculator with your actual figures.
| Withdrawal Rate | 3% Return | 5% Return | 7% Return | Assessment |
|---|---|---|---|---|
| 3.0% | Indefinite | Indefinite | Indefinite | Ultra-conservative — FIRE-grade safety |
| 3.5% | Indefinite | Indefinite | Indefinite | Highly sustainable for 40–60 yr horizons |
| 4.0% | ~38 yrs | Indefinite | Indefinite | Trinity Study "safe" rate for 30 yrs |
| 5.0% | ~26 yrs | Indefinite | Indefinite | Sustainable at moderate returns |
| 6.0% | ~19 yrs | ~38 yrs | Indefinite | Risky at low returns |
| 7.0% | ~15 yrs | ~25 yrs | Indefinite | Only viable with higher growth |
| 8.0% | ~13 yrs | ~20 yrs | ~38 yrs | Aggressive — plan B required |
| 10.0% | ~10 yrs | ~14 yrs | ~20 yrs | Short-term bridge use only |
Assumes fixed nominal withdrawal and constant annual return. Inflation-adjusted withdrawals and year-to-year return volatility will produce different results — use the full calculator for your specific scenario.
The Variable Percentage Withdrawal strategy calculates each year's withdrawal as a percentage of the current portfolio balance, based on remaining life expectancy and expected return. Unlike fixed-dollar withdrawals, VPW never depletes the portfolio to zero — withdrawals decline as the portfolio shrinks in bad years and rise in good years. VPW maximizes lifetime spending while guaranteeing the portfolio lasts the full expected retirement period. It is more complex than a fixed withdrawal but produces superior outcomes for most retirees.
The VPW percentage schedule derives from solving the annuity present value formula for the payment that exactly exhausts the portfolio at end of the expected horizon. At age 65 with a 30-year horizon and 5% return, VPW yields a first-year withdrawal of roughly 5.3% — higher than the 4% rule — because it accounts for the shortening remaining lifespan. As the retiree ages, the VPW percentage rises, automatically increasing spending in later years when it is warranted while protecting capital in down-market years when the percentage applied to a lower balance produces a smaller dollar amount.
A lifetime annuity transfers longevity risk to an insurance company: you pay a lump sum and receive guaranteed monthly income for life, regardless of how long you live. Immediate annuities currently pay about 6–7% annual income on the purchase price for a 65-year-old. Covering basic expenses with a combination of Social Security and a small annuity — while keeping the bulk of the portfolio invested — provides a longevity floor without sacrificing all the upside of investment returns. This hybrid approach is increasingly recommended by academic retirement researchers.
Deferred income annuities (DIAs), also called longevity annuities, are particularly cost-effective: purchased at 65 to start payments at 80 or 85, they hedge the extreme tail of longevity risk at a fraction of the cost of an immediate annuity. Allocating 10–20% of the portfolio to a DIA at retirement and investing the remaining 80–90% in equities often produces better expected lifetime income than either a pure investment portfolio or a pure annuity approach alone.
Large required minimum distributions (RMDs) in your 70s can force you into higher tax brackets, effectively increasing the gross withdrawal needed to fund after-tax spending. Converting traditional IRA funds to Roth during lower-income years (early retirement before Social Security, before RMDs) reduces future RMDs and creates tax-free income. The Roth conversion ladder requires careful planning but can significantly extend after-tax portfolio longevity by reducing the tax drag on withdrawals.
The mathematics of Roth conversions interact directly with the longevity formula: if a $60,000 after-tax withdrawal requires $75,000 gross from a traditional IRA at a 20% effective rate, the real PMT in the longevity formula is $75,000 — not $60,000. Converting $200,000 to Roth over a 5-year window before RMDs begin can reduce the effective tax rate on withdrawals from 22% to 12%, lowering the gross withdrawal required and potentially extending portfolio life by 3–7 years for retirees with large traditional account balances.
For homeowners, home equity is a significant unleveraged asset that can serve as a late-retirement longevity reserve. A reverse mortgage allows retirees 62+ to draw income from home equity without selling, with repayment deferred until the home is sold or the owner moves. Downsizing releases substantial equity to reinvest at a higher return than illiquid real estate provides. Incorporating home equity into longevity planning — while maintaining the portfolio for daily expenses — provides an additional buffer that many retirees overlook when running their first longevity calculation.
One of the most consequential choices in running a longevity calculation is whether to use nominal or inflation-adjusted (real) figures. A nominal model uses a fixed dollar withdrawal and an unadjusted return rate — simpler and always showing a longer longevity result. A real model either increases the withdrawal annually by the inflation rate, or deflates the return rate to a real figure (nominal return minus inflation) and keeps the withdrawal fixed. Both approaches reach the same answer when done correctly, but confusing the two — using a nominal return with an inflation-growing withdrawal — double-counts inflation and produces an artificially pessimistic result.
The correct conservative planning approach is to use real (inflation-adjusted) figures throughout. If your portfolio earns 7% nominally and inflation runs at 3%, use a 4% real return and a fixed real withdrawal. This eliminates inflation complexity while keeping the projection grounded in purchasing power. Alternatively, use the nominal 7% return and grow the withdrawal by 3% annually in the calculator — both methods should produce identical longevity results when inputs are consistent. Our calculator supports both approaches; choose nominal when modeling a truly fixed-dollar income stream, and inflation-adjusted when modeling spending that will keep pace with rising costs.
Most retirees hold assets across multiple account types — taxable brokerage accounts, traditional IRAs and 401(k)s (pre-tax), and Roth IRAs (after-tax). The order in which you draw from these accounts dramatically affects how long your money lasts in after-tax terms. The conventional wisdom of spending down taxable accounts first, then traditional IRAs, then Roth accounts is often suboptimal. A coordinated withdrawal strategy — filling lower tax brackets each year with traditional IRA withdrawals while letting Roth assets continue compounding — can reduce lifetime tax payments by tens of thousands of dollars and extend effective portfolio longevity accordingly.
The optimal withdrawal sequence depends on your current tax bracket, projected future brackets, state income taxes, Medicare premium surcharges (IRMAA), and estate planning goals. For retirees with large traditional IRA balances, the priority in the window between retirement and age 73 is often strategic Roth conversions to the top of the 22% or 24% bracket — reducing the future RMD burden while locking in current tax rates. A fee-only financial planner running a Roth conversion analysis alongside the money longevity calculation can identify sequences that meaningfully extend the portfolio's practical lifespan.
The money longevity calculator is not just a tool for retirees — it is valuable at every stage of financial planning. For workers in their 40s and 50s, running a longevity projection with a planned retirement date 10–20 years out reveals whether the current savings trajectory is adequate and how sensitive the outcome is to changes in savings rate, return assumptions, or retirement age. Discovering a funding gap at 50 is far more actionable than discovering it at 65 — there is still a decade or more to correct course.
For retirees in the early withdrawal phase (ages 62–75), longevity projections should be revisited annually because this is the highest-risk window. Sequence-of-returns risk is most severe when the portfolio is at its largest relative to withdrawals. An annual check-in — plugging the actual current portfolio balance into the calculator with the actual current withdrawal rate — reveals whether the plan remains on track or whether modest adjustments are warranted before a small shortfall compounds into a crisis.
For late retirees (ages 80+), longevity planning shifts toward managing required minimum distributions, healthcare cost reserves, and potential long-term care funding. The portfolio has typically survived its highest-risk phase, and the remaining question is sequencing assets across a shorter remaining horizon while managing tax exposure and ensuring sufficient liquidity for healthcare needs. The same longevity formula applies — but with a shorter n, a potentially lower return assumption (more conservative allocation), and a higher withdrawal rate driven by increasing healthcare costs.
This quick-reference grid shows how long common portfolio sizes last at a fixed 5% annual return, across four annual withdrawal levels. Use it to orient your plan before running the full calculation. Figures assume constant returns and fixed nominal withdrawals.
| Portfolio Size | $30k/yr | $40k/yr | $50k/yr | $60k/yr |
|---|---|---|---|---|
| $500,000 | Indefinite | ~17 yrs | ~12 yrs | ~10 yrs |
| $600,000 | Indefinite | ~25 yrs | ~15 yrs | ~12 yrs |
| $750,000 | Indefinite | Indefinite | ~21 yrs | ~15 yrs |
| $1,000,000 | Indefinite | Indefinite | ~30 yrs | ~22 yrs |
| $1,250,000 | Indefinite | Indefinite | Indefinite | ~32 yrs |
| $1,500,000 | Indefinite | Indefinite | Indefinite | Indefinite |
At 5% return, a portfolio is self-sustaining when the withdrawal amount equals or falls below 5% of the starting balance. “Indefinite” means the portfolio grows over time. All figures are nominal; inflation-adjusted withdrawals deplete the portfolio faster.
Use this checklist to confirm you have accounted for the key factors before finalizing your retirement longevity plan. Each item represents a variable that can meaningfully change your projection if overlooked.
Calculated total portfolio value across all accounts (brokerage, IRA, 401k, Roth)
Include all invested assets, not just primary retirement accounts.
Subtracted guaranteed income (Social Security, pension) from annual withdrawal requirement
Net withdrawal = total spending minus guaranteed income.
Adjusted savings goal for inflation if retirement is 3+ years away
Multiply today's spending estimate by (1.03)^years to retirement.
Modeled at least three return scenarios: 3%, 5%, and 7%
Verify the 3% scenario still produces an acceptable outcome.
Set planning horizon to age 90 or 95, not average life expectancy
Average life expectancy = 50% chance of outliving your funds.
Budgeted for at least one large healthcare expense
Model a $100,000–$200,000 one-time cost in years 10–20 of retirement.
Reviewed asset allocation: at least 40% equity for 20+ year horizons
All-bond or all-cash portfolios risk inflation eroding the real withdrawal capacity.
Set a calendar reminder to re-run the calculation annually
Use actual current balance — not the original projected figure — each year.
Considered delaying Social Security to age 70 for maximum benefit
Each year of delay from 62 to 70 increases the benefit by 6–8%.
Reviewed withdrawal strategy: fixed dollar vs. flexible guardrails vs. VPW
Flexible strategies consistently outperform fixed-dollar rules in longevity studies.
Complete your retirement planning with these complementary tools that work alongside the money longevity calculator.
Retirement Calculator
Build your full retirement projection including accumulation and withdrawal phases.
FIRE Calculator
Calculate your financial independence number and years to reach it at any savings rate.
Coast FIRE Calculator
Find the point where your savings can grow to your retirement target without further contributions.
Future Value Calculator
Project your portfolio balance at retirement given current savings and contributions.
Compound Interest Calculator
Model how your investments compound during the growth phase before retirement.
Savings Goal Calculator
Find the monthly contribution needed to hit your retirement savings target.
Investment Return Calculator
Calculate historical and projected returns on your retirement portfolio.
Inflation Calculator
See how inflation erodes purchasing power and adjust your withdrawal targets accordingly.
Net Worth Calculator
Measure your total financial position including all retirement assets and liabilities.
SIP Calculator
Calculate how systematic monthly investments build toward your retirement goal.
The money longevity calculator — also called a how-long-will-money-last calculator — tells you how many years a savings or investment portfolio will last given a fixed annual withdrawal amount, starting balance, and expected investment return. It is the essential tool for retirement planning: once you stop earning income, you need to know whether your nest egg will outlast your retirement years or run dry prematurely.
To calculate how long money will last, the formula is: n = -ln[1 - (PV × r) / PMT] / ln(1 + r), where PV is the starting portfolio value, r is the periodic return rate (annual / 12 for monthly), and PMT is the periodic withdrawal. This solves for n, the number of periods until the portfolio reaches zero. Our calculator uses a period-by-period simulation: each month it credits interest, deducts the withdrawal, and continues until the balance hits zero.
The 4% rule is a retirement planning guideline that suggests withdrawing 4% of your portfolio in year one of retirement, then adjusting that dollar amount annually for inflation. Research (the Trinity Study) found that a 60/40 portfolio using this withdrawal rate historically lasted at least 30 years in 95%+ of historical scenarios. It implies you need 25 times your annual spending to retire safely. The 4% rule is a starting point, not a guarantee — actual longevity depends on portfolio allocation, sequence of returns, and spending flexibility.
A portfolio lasts indefinitely when the withdrawal rate equals or falls below the sustainable withdrawal rate — historically estimated at 3–3.5% for a 50-year+ retirement horizon. At this rate, withdrawals are fully funded by investment returns, and the portfolio balance is maintained or grows. For a $1,000,000 portfolio at a 7% real return: a $35,000 withdrawal (3.5%) leaves a growing surplus. Above 7% withdrawal ($70,000+), the portfolio will eventually deplete. The exact sustainable rate depends on asset allocation and return sequence.
Inflation erodes purchasing power, effectively increasing the real withdrawal amount each year even if you withdraw the same nominal dollar amount. If you withdraw $40,000/year nominally but inflation runs at 3%, your purchasing power falls by $1,200 in real terms each year. Most money longevity calculators let you input either a fixed nominal withdrawal or inflation-adjusted withdrawals that increase annually. Inflation-adjusted projections are more realistic and typically show the portfolio depleting faster than nominal-withdrawal models suggest.
Sequence of returns risk is the danger that a portfolio will deplete prematurely if significant market losses occur in the early years of retirement, when the portfolio is at its largest and withdrawals are at their full dollar amount. A 30% market drop in year 2 of retirement forces you to sell more shares at depressed prices to fund withdrawals — shares that would have recovered over the subsequent decade if left untouched. Mitigations include maintaining a 1–2 year cash buffer, reducing withdrawals temporarily during downturns, and holding a bond allocation for stability.
With a $1,000,000 portfolio earning 5% annually and a $50,000/year withdrawal: money lasts about 30 years. At $40,000/year (4% rule): lasts 36+ years. At $60,000/year (6%): lasts about 22 years. At $70,000/year: about 18 years. These estimates assume constant returns — actual longevity varies with market performance. Adding Social Security or other income streams reduces the required portfolio withdrawal, dramatically extending longevity. Inflation-adjusted spending ($50,000 growing at 3%/year) depletes the portfolio faster than fixed-dollar models show.
With $500,000 earning 5% annually: at $25,000/year withdrawal it lasts indefinitely (5% return = $25,000). At $30,000/year: about 27 years. At $40,000/year: about 17 years. At $50,000/year: about 12 years. $500,000 is typically insufficient as a sole retirement fund for 30+ year retirements at modest spending levels without significant income supplements. Paired with Social Security (average benefit ~$22,000/year), a $500,000 portfolio providing $20,000/year creates a combined $42,000/year income — potentially sustainable for 30+ years.
The Trinity Study (1998, updated multiple times since) is a landmark academic study by three Trinity University finance professors analyzing historical portfolio survival rates at different withdrawal rates and stock/bond allocations. It found that a 4% withdrawal rate on a 75% stock / 25% bond portfolio had a 95%+ success rate over 30-year retirement periods using historical U.S. market data. The study is the empirical foundation of the 4% rule. Critics note it is based on historical U.S. data and may not reflect future returns or international market conditions.
Flexible withdrawal strategies outperform fixed-rate rules in both portfolio longevity and lifetime spending. In bad market years, reducing withdrawals by 10–15% preserves capital and dramatically extends portfolio life. In good years, modest spending increases can be permitted. The guardrails method (set a floor and ceiling withdrawal rate) formalizes this flexibility while maintaining a spending baseline. Rigid fixed withdrawals force you to sell into market downturns at the worst possible time — flexibility is the single most powerful tool for improving retirement portfolio longevity.
Social Security income directly reduces the withdrawal required from your portfolio, dramatically improving longevity. If you need $50,000/year and receive $20,000 from Social Security, your portfolio only needs to fund $30,000/year — a 40% reduction in withdrawal rate. Delaying Social Security from age 62 to 70 increases your benefit by 76% (8% per year from 66 to 70). This delay, funded by drawing slightly more from the portfolio early, typically improves lifetime income and portfolio longevity for most retirees.
Run the money longevity calculator three times: optimistic (8% return), base case (5–6% return), and pessimistic (3% return). For retirement planning, the pessimistic scenario should still show an acceptable outcome — if your money only lasts 20 years in the worst case but you expect to need 30, you need to reduce spending, increase the portfolio, or plan other income supplements. Running all three scenarios reveals the range of outcomes and helps you make robust decisions that hold up even under adverse conditions.
For a 30-year retirement horizon, research suggests 3.5–4.0% is a historically safe withdrawal rate for a balanced portfolio (60% stocks / 40% bonds). For a 40-year retirement (retiring at 55), research suggests 3.0–3.5% is safer. For a 20-year retirement (retiring at 70), 4.5–5.0% may be feasible. These rates assume inflation-adjusted spending; a fixed nominal withdrawal can sustain a higher initial rate. Always model below the historical safe rate to account for potentially lower future returns versus historical averages.
A higher stock allocation increases expected returns and portfolio longevity — but with more volatility. A 100% stock portfolio has a higher expected longevity than a 100% bond portfolio at the same withdrawal rate, but can drop 40–50% in a bad year, triggering excessive selling. Research finds that 40–70% equity allocations balance growth and stability optimally for most retirement scenarios. All-bond portfolios are often too conservative; at current yields, they may not keep pace with inflation plus withdrawals over 30+ years.
The bucket strategy divides retirement assets into three time-based buckets: Bucket 1 — 1–2 years of expenses in cash/money market (immediate spending); Bucket 2 — 3–10 years in bonds and conservative investments (medium-term replenishment); Bucket 3 — 10+ years in equities (long-term growth). Withdrawals come from Bucket 1; Bucket 2 replenishes Bucket 1 annually; Bucket 3 grows and eventually replenishes Bucket 2. This structure insulates day-to-day spending from equity market volatility and emotionally supports retirees through market downturns.
Required minimum distributions (RMDs) force withdrawals from traditional IRA and 401(k) accounts starting at age 73 (current law). RMD amounts are calculated as account balance divided by an IRS life expectancy factor, starting at roughly 3.7% of the account at 73 and increasing each year. If your RMD exceeds your spending needs, the excess must be withdrawn and taxed regardless. Large RMDs from oversized traditional accounts can push retirees into higher tax brackets. Roth conversions before RMD age reduce this problem by converting to tax-free Roth funds.
Large one-time expenses — a home renovation, major medical procedure, or long-term care cost — can significantly accelerate portfolio depletion if not planned for. A $100,000 unplanned expense at year 10 of a 30-year retirement can shorten the portfolio's life by 2–4 years. Planning for expected large expenses (new car every 7 years, HVAC replacement, etc.) by maintaining a separate sinking fund prevents these costs from hitting the core retirement portfolio when markets may be down.
Part-time work income in early retirement is disproportionately valuable because it reduces portfolio withdrawals during the most critical sequence-of-returns period (years 1–10 of retirement). Even earning $15,000/year from part-time work on a portfolio withdrawing $50,000/year reduces the withdrawal by 30% — potentially adding 5–10 years to portfolio longevity. The first decade of retirement is when portfolios are most vulnerable to depletion; any income that reduces withdrawals during this window has an outsized positive impact.
Paying off the mortgage before retirement reduces mandatory monthly spending, lowering the required portfolio withdrawal and extending longevity. A $1,500/month mortgage payment requires an extra $18,000/year from the portfolio — at a 4% withdrawal rate, that mortgage effectively requires $450,000 more in the portfolio. For retirees with mortgages carrying rates above their expected portfolio return, payoff often makes mathematical and psychological sense. For those with low-rate mortgages (under 3%), investing the payoff funds may produce better expected outcomes.
With a 0% investment return, the calculation is simply: years = portfolio balance / annual withdrawal. $500,000 at $25,000/year = 20 years. $1,000,000 at $50,000/year = 20 years. $1,000,000 at $40,000/year = 25 years. This is the worst-case scenario — money held entirely in cash earning nothing. In practice, even a conservative bond portfolio earns 2–3% annually, extending the timeline meaningfully. The 0% scenario illustrates the critical importance of maintaining some investment return even in retirement.
Longevity risk is the risk of outliving your money — living longer than your retirement savings can support. Americans who reach age 65 have a median life expectancy of about 85 for women and 83 for men, but planning to age 85 means a 50% chance of outliving your funds. Financial planners recommend planning to age 90–95 to account for longevity. Longer life expectancy, combined with rising healthcare costs and inflation, makes running the money longevity calculation with a 30+ year horizon essential for anyone retiring before 70.
Healthcare costs inflate faster than general CPI — historically at 5–7% annually compared to 2–3% for general inflation. A retiree spending $10,000/year on healthcare at age 65 may face $27,000/year by age 85 (at 5% healthcare inflation). This accelerating cost is the primary driver of retirement underfunding for many retirees. Long-term care insurance, a Health Savings Account (HSA) built up pre-retirement, and Medicare supplemental insurance are the primary tools for managing healthcare longevity risk in a retirement plan.
Yes. The money longevity calculator applies to any situation where a lump sum is being drawn down over time: a college savings fund supporting a student's annual tuition withdrawals; a severance payment being used during a job search; an inheritance being drawn down to supplement income; a disability insurance fund. Any scenario where a starting balance is being spent at a regular rate — with or without investment return — can be modeled with this calculator. The mathematics is identical regardless of the specific purpose.
A Monte Carlo simulation runs thousands of retirement scenarios with randomly varying annual returns drawn from a historical distribution, then reports the percentage of scenarios in which the portfolio lasts the specified number of years. A 90% success rate means the portfolio lasted the full retirement period in 90% of simulated scenarios. Professional financial planning software uses Monte Carlo to answer probabilistic questions that a single fixed-return model cannot address. A 90%+ Monte Carlo success rate is typically the target for robust retirement planning.
Dynamic spending adapts annual withdrawals to portfolio performance rather than following a fixed rule. Common frameworks include: (1) the guardrails method — raise or cut spending when withdrawal rate crosses a ceiling or floor threshold; (2) the RMD method — withdraw the RMD amount regardless of other factors; (3) a fixed percentage — withdraw a fixed % of the current balance annually, which naturally shrinks in bad years. Dynamic spending studies consistently show better portfolio longevity and higher lifetime spending compared to rigid fixed-dollar rules.
Delaying retirement by even 1–2 years improves portfolio longevity in three ways simultaneously: (1) you contribute more to the portfolio during working years; (2) you have fewer years to fund in retirement (shorter withdrawal period); (3) the portfolio has more time to compound before withdrawals begin. Delaying from age 62 to 65 on a $500,000 portfolio at 7% growth adds $112,000 to the starting balance while reducing the required withdrawal period by 3 years — a dramatic improvement in longevity from a relatively modest change in timing.
Diversification — spreading investments across asset classes (stocks, bonds, real estate, international) — reduces the portfolio's volatility without proportionally reducing expected return. Lower volatility directly improves money longevity by reducing the severity of early-retirement drawdowns that trigger sequence-of-returns risk. A globally diversified portfolio of low-cost index funds has historically provided better risk-adjusted returns (and therefore better longevity) than concentrated portfolios. Diversification is the only free lunch in finance — more stability at no cost in expected return.
Beyond our money longevity calculator, professional tools include: FIRECalc (uses historical market sequences to test withdrawal scenarios), Portfolio Visualizer (Monte Carlo and backtesting), cFIREsim (detailed FIRE retirement modeling), and NewRetirement (comprehensive planning platform). For most individuals, our calculator provides sufficient insight for initial planning and regular check-ins. For comprehensive retirement plans — especially those within 5–10 years of retirement — working with a fee-only financial planner using professional Monte Carlo software is worthwhile.
Financial planners typically recommend building a 20–30% buffer above the minimum portfolio size the longevity calculation suggests. If the calculator shows you need $800,000 to fund a 30-year retirement at your spending level, targeting $960,000–$1,040,000 provides a margin for unexpected spending, suboptimal returns, or longer-than-expected retirement. This buffer acknowledges the uncertainty of fixed-return projections and reduces the risk of underfunding — the most financially and emotionally damaging retirement outcome.
The FIRE (Financial Independence, Retire Early) movement uses a 3.0–3.5% withdrawal rate rather than the standard 4% rule, because early retirees face 40–60+ year retirement horizons rather than 25–30 years. FIRE adherents also typically maintain flexibility to reduce spending in market downturns and may return to part-time work if needed. The FIRE community's emphasis on building a large enough nest egg (33× annual spending at 3%) and maintaining spending flexibility makes the money longevity calculator a foundational planning tool.
Sustainable Withdrawal Rate
The maximum annual withdrawal percentage at which a portfolio never depletes — where investment return equals or exceeds the withdrawal. At a 5% return, withdrawing exactly 5% of the starting balance is sustainable indefinitely in nominal terms. Below this rate, the portfolio grows; above it, the portfolio shrinks toward zero.
Sequence Risk vs. Market Risk
Market risk is the chance of permanent loss. Sequence risk is the chance of temporary losses at the worst possible time — early retirement. A portfolio can experience identical average returns over 30 years but deplete in year 20 if the bad returns came first. Sequence risk is the dominant retirement planning risk, not average return.
Nominal vs. Real Longevity
Nominal longevity is measured in years until the portfolio balance hits zero in current dollars. Real longevity adjusts for inflation — a portfolio lasting 30 years nominally may only last 22 years in purchasing-power terms if inflation is not modeled. Always verify which measure a calculator reports.
Floor vs. Upside Portfolio Strategy
The floor-and-upside approach separates retirement assets into a floor (guaranteed income for essential needs via Social Security, pension, annuity) and an upside portfolio (invested for growth, funding discretionary spending). This structure eliminates sequence risk on essential expenses while preserving growth potential for the remainder.
Calculation method:This calculator uses a year-by-year simulation. Each year, the portfolio balance is multiplied by (1 + annual return rate), and the annual withdrawal (optionally inflation-adjusted) is subtracted. The process continues until the balance reaches zero or 100 years are modeled. The closed-form formula n = -ln[1 - (PV × r) / PMT] / ln(1 + r) is used for verification. Results assume constant annual returns — actual returns vary significantly year to year.
Disclaimer: This calculator is for educational and illustrative purposes only. Retirement projections depend on many uncertain variables including future market returns, inflation, healthcare costs, and life expectancy. Results are not guarantees of portfolio survival. Always consult a qualified financial advisor or certified financial planner for personalized retirement planning. Last updated: June 2026. Maintained by Financial Growth Hub.
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