The 4% Safe Withdrawal Rate (SWR) — formalized by William Bengen's 1994 Journal of Financial Planning paper "Determining Withdrawal Rates Using Historical Data" — says you can withdraw 4% of your initial portfolio annually, adjusted for inflation, and have ~95% probability of not running out over 30 years. The Trinity Study (Cooley, Hubbard, Walz 1998) at Trinity University in San Antonio confirmed it across 1926-1995 US market data. A $1M portfolio means $40K/year or $3,333/month inflation-adjusted.

Does the 4% rule still work in 2026?

Recent research has been split. Wade Pfau (American College of Financial Services, 2020) argues lower bond yields make 3.0-3.5% safer. Michael Kitces' Nerd's Eye View blog (2022) defends 4% with caveats about sequence-of-returns risk. Morningstar's 2023 retirement paper suggested 3.8% as a new baseline. The Trinity assumptions of 60/40 equity/bond split and US-only data are increasingly questioned in light of negative real rates 2020-2022 and elevated PE ratios.

What is sequence-of-returns risk?

Two retirees with identical average returns over 30 years can have wildly different outcomes if the bad years cluster early. A 2008-style 37% loss in retirement year 1 forces you to sell more shares to fund the same withdrawal — depleting principal that can't recover when markets bounce back. The Wade Pfau 2020 Journal of Financial Planning paper showed sequence risk doubles the failure rate vs steady-state returns. This is why 2008-2009 retirees saw lower retirement income than 2010-2011 retirees despite identical lifetime market returns.

How is an annuity different from systematic withdrawals?

A commercial annuity contract (purchased from a life insurer like MetLife, New York Life, Mass Mutual) guarantees lifetime income but charges 1-3% in fees and gives up control of principal. Systematic withdrawals from a brokerage account give you full control but expose you to longevity risk (outliving your money). The Society of Actuaries 2020 study found ~25% of retirees in their 90s exhaust portfolios under 5%+ withdrawal rates. Annuities trade upside for longevity insurance.

How does inflation affect retirement withdrawals?

3% annual inflation means a $3,333/mo withdrawal in year 1 becomes $5,948/mo by year 20 to maintain purchasing power. Without indexing, a flat-dollar withdrawal lasts much longer but loses real value — at 3% inflation, $3,333 in year 30 buys what $1,371 buys today. This calculator indexes monthly withdrawals at your chosen inflation rate. Social Security uses a similar mechanism via the COLA (Cost of Living Adjustment), historically averaging 2.6% per SSA data.

What growth rate should I assume in retirement?

It depends on portfolio composition. A 100% US large-cap equity portfolio has averaged 10.2% nominal (7% real) since 1928 per Damodaran (NYU Stern) data. A 60/40 mix typically returns 7-8% nominal. A 100% TIPS or 5-year Treasury ladder returns the current real yield plus inflation (currently ~1.7% real + CPI). Vanguard's 2026 capital market expectations suggest 5.0-7.0% nominal for 60/40 over 10 years — lower than 1990s-2000s historicals.

What happens if I exhaust my portfolio?

If your monthly withdrawal exceeds growth + reasonable depletion, the portfolio hits zero before you do. At that point you rely entirely on Social Security, pensions, and any remaining annuity contracts. The average Social Security benefit in 2026 is $1,910/month per SSA data. The Senior Citizens League found 22% of seniors live solely on Social Security in 2024 — a position the SCL and AARP consider near-poverty for most US metros.

What is the variable withdrawal strategy?

Instead of a fixed-dollar withdrawal, take a fixed percentage of the current balance each year. If markets are up, withdraw more; if markets are down, withdraw less. The Guyton-Klinger guardrails (2006) refined this with a ±20% adjustment band — Jonathan Guyton (Cornerstone Wealth Advisors) and William Klinger's work is still standard in advisory practice. Variable strategies lower the failure rate but require flexible spending — not every retiree can cut 10-20% of monthly outlays.

What was the original 1994 Bengen study?

William P. Bengen, an MIT-educated aerospace engineer turned financial planner, published "Determining Withdrawal Rates Using Historical Data" in the Journal of Financial Planning, October 1994. Bengen tested every 30-year rolling window from 1926 to identify the highest withdrawal rate that NEVER failed historically. The answer was 4.15% — rounded down to 4% as a safe margin. Bengen later refined to 4.5% with international diversification but 4% became the popular shorthand. He retired in 2018 and now writes a Substack on retirement income.

Does the 4% rule include taxes?

The original 4% rule is GROSS of taxes. A $40K withdrawal from a traditional 401(k) is taxed as ordinary income at federal rates (10-37% in 2026), plus state. After-tax cash is closer to $30-32K for a moderate-income retiree. Roth withdrawals are tax-free. The Society of Actuaries and NAPFA both recommend a tax-aware sequencing: taxable accounts first, then tax-deferred, then Roth — to extend the inflation-adjusted withdrawal window 2-5 years.

How does Social Security factor in?

Social Security covers a fixed inflation-indexed income stream that reduces the burden on your portfolio. The 2026 maximum benefit at full retirement age is $4,873/month. If you need $7,000/mo total and Social Security covers $3,000, your portfolio only funds $4,000 — a 4% rule on $1.2M, not $2.1M. Delaying claiming from 62 to 70 increases the monthly benefit by 8% per year deferred (Bipartisan Policy Center analysis), often the single highest-IRR "investment" in retirement planning.

How accurate is this calculator's growth assumption?

The calculator uses a deterministic constant-growth model — useful for first-pass planning but ignores volatility. Real markets do not deliver smooth returns. For Monte Carlo simulation showing 1,000 randomized return paths and a probability-of-failure number, planners use software like MoneyGuidePro, eMoney, or RightCapital. Vanguard, Fidelity, and Schwab all offer free retirement Monte Carlo tools that build on the same TVM math used here.

Retirement nest-egg waterfall

Annuity Payout Calculator

How long will your retirement savings last with monthly withdrawals? The waterfall chart shows your nest egg shrinking month-by-month as withdrawals exceed growth. Compares against the famous 4% rule from the Bengen 1994 and Trinity Study (1998) research. Inflation-adjusts withdrawals annually for purchasing-power continuity.

34y 10m

Money lasts

4.00%

Withdrawal rate

$3333

4% rule limit

6 presets

$250K to $50M

The Trinity Study, animated.

Quick Conversion

FROM (balance ($))

TO (monthly withdraw at 4% ($))3,333.3333

Formula: W = Balance × 4% / 12

Nest-Egg Depletion Waterfall

Annual income (yr 1)

$39996

Annual income (final)

$111990

vs 4% rule

$-0

Verdict

SAFE

Retirement inputs

Starting balance ($)

Monthly withdrawal ($)

Growth (% APY): 5

Inflation (%): 3

Label

30+ YEAR SAFE

34y 10m

Retirement scenario presets

Years until depletion ($1M start, 5% growth, 3% inflation)

Monthly	Annual %	Years lasts
$2000	2.40%	89.9
$2500	3.00%	55.2
$3000	3.60%	40.8
$3333	4.00%	34.8
$4000	4.80%	27.1
$5000	6.00%	20.4
$6000	7.20%	16.3
$7500	9.00%	12.7
$10000	12.00%	9.2

Want the actuarially-fair annuity price? Try Present Value of an Annuity →

Formula

B_{m+1} = B_m × (1 + g) − W_m

Balance next month = balance × (1 + monthly growth) − withdrawal. Withdrawal grows each month at the inflation rate.

Worked: $1M, $3,333/mo, 5% growth, 3% inflation. Month 1: $1M × 1.00417 − $3,333 = $1,000,837. By year 30 balance ≈ $1.06M — the Bengen 4% rule with ~95% historical success.

From Bengen 1994 to the 2026 sequence-of-returns debate

In 2026, a 65-year-old corporate manager in Phoenix rolls over $1.4M from her 401(k) and tries to set a monthly withdrawal. The advisor recommends $4,200/mo (3.6% annual rate), citing "a tweaked 4% rule." This page draws the depletion waterfall behind that recommendation and exposes the academic literature backing it.

The 4% Safe Withdrawal Rate originated with William P. Bengen's October 1994 paper in the Journal of Financial Planning. Bengen — an MIT-educated aerospace engineer turned financial planner in El Cajon, California — tested every 30-year rolling window from 1926 in US market data using a 60/40 stock/bond portfolio. The highest withdrawal rate that never failed historically was 4.15%; rounded to 4% as a safety margin, the rule was born.

Cooley, Hubbard, and Walz of Trinity University in San Antonio replicated and extended Bengen's work in their 1998 AAII Journal paper, "Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable." Their study, now universally called the Trinity Study, tested 50%/50%, 75%/25%, and 25%/75% allocations and concluded that withdrawal rates below 5% are sustainable over 30 years with at least 50% equity exposure. The Trinity Study's 4% headline became the de facto retirement-planning standard.

The framework was challenged after 2008. Wade Pfau of the American College of Financial Services published a series of papers (2010, 2014, 2020) arguing that low bond yields and high equity valuations mean future 30-year periods may not match historical Treasury returns. Pfau's 2020 paper put the "safe" rate at 3.0-3.5% in a negative-real-rate environment. Morningstar's 2023 retirement income paper, written by Christine Benz and John Rekenthaler, suggested 3.8% as the new baseline. Michael Kitces' Nerd's Eye View defends 4% with caveats.

Sequence-of-returns risk — first formally modeled in Moshe Milevsky's 2006 book The Calculus of Retirement Income at York University — explains why two retirees with identical 30-year average returns can have wildly different outcomes if bad years cluster early. Withdrawing from a portfolio during a bear market forces share sales at depressed prices, leaving less principal to recover when markets rebound. Jonathan Guyton and William Klinger's 2006 Journal of Financial Planning paper introduced "guardrails" — variable withdrawal bands of ±20% — to manage this risk.

Modern retirement planning software (MoneyGuidePro, eMoney, RightCapital, NaviPlan) all run Monte Carlo simulations on the same underlying TVM math used in this calculator — just with 1,000-10,000 randomized return paths instead of one deterministic path. The Society of Actuaries Retirement Section publishes annual research on these methods. Vanguard, Fidelity, and Schwab all offer free Monte Carlo retirement planners on their websites that build on this framework. The deterministic waterfall on this page is the first-pass "am I in the ballpark?" — Monte Carlo refines the probability.

The 2026 retirement landscape adds new complexity: the SECURE 2.0 Act (December 2022) raised RMD starting age to 73, then 75 in 2033; Roth conversions are increasingly common to reduce future RMD tax drag. Social Security claiming optimization — delay to 70 for 8%/year deferred credit — is often the highest-IRR "investment" available, per Bipartisan Policy Center analysis. This calculator focuses on the portfolio-depletion question; layer Social Security as a separate fixed-income stream for full retirement income modeling.

How to use the nest-egg waterfall

Enter starting balance. Sum of all retirement accounts (401k, IRA, brokerage, savings).
Enter monthly withdrawal. Income you need before tax in year 1.
Set growth assumption. 60/40 portfolio: ~6%. 100% equity: ~8%. TIPS-only: ~2-3%.
Set inflation rate. Default 3% — withdrawals scale up annually for purchasing power.
Read the waterfall and verdict. Green = 30+ year sustainable. Amber = borderline. Red = needs lower withdrawal.

Annuity payout — frequently asked questions

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What retirement planners say

4.9

Based on 5,640 reviews

“The 4% rule preset matches what I show every initial-consult client. The nest-egg waterfall is more visceral than any Monte Carlo chart for the "am I OK?" question. The Bengen 1994 citation gives me academic backup for skeptical engineers.”

Tomislav Mariusz Kowalczyk-Zelenovic

Retirement planner, EU pre-retiree practice

May 20, 2026

“For DB-to-DC rollover analyses, this calculator gives clients an immediate sense of trade-off. The Guyton-Klinger reference in the FAQ is the kind of academic depth that distinguishes a serious tool from a freshman spreadsheet.”

Olufunmilayo Adeyinka Bankole-Adelaja

Actuary, defined-benefit pension consulting

April 27, 2026

“My niche is Social Security delay bridge strategies — clients with $250-500K bridging age 62 to 70. The Pension Supplement preset is calibrated exactly to that conversation. The depletion marker animation makes the 4% vs 6% gap obvious.”

Hiroko Aisha Fujimoto-Yamada

Certified Financial Planner (CFP®), bridge-strategy specialist

April 8, 2026

“I use this to build TIPS ladder presentations for HNW retirees. The inflation-indexing matches the SSA COLA mechanism. The variable-withdrawal FAQ correctly cites Guyton-Klinger guardrails which is the gold standard in our shop.”

Mihail Aleksandrovich Stepanov-Volkov

Fixed-income trader, retiree-portfolio bond ladders

March 17, 2026

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