Safe Withdrawal Rate Calculator

Run 2,000 simulated markets to see the chance your portfolio lasts and the highest withdrawal rate that survives.

Assumptions reviewed

$
$
years
% stocks
% / yr
% / yr
% / yr
Risky
Chance your money lasts
80.9%

Below 85%: consider a lower withdrawal, a longer working period, or part-time income early in retirement.

Portfolio over retirement (today's $)
Bad markets (10th pct)Typical (median)Good markets (75th pct)
$0$2M$4M$6M$8M061218243036Years into retirement
Your withdrawal rate
4%
Highest rate with 95% success
2.75%
Safe yearly withdrawal (95%)
$34,375
Typical ending balance
$2,385,651
Bad-case ending balance (10th percentile)
$0
Success rate by withdrawal rate
0%20%40%60%80%100%3% — Chance money lasts: 93.3%3%3.5% — Chance money lasts: 88.15%3.5%4% — Chance money lasts: 80.85%4%4.5% — Chance money lasts: 71.4%4.5%5% — Chance money lasts: 60.8%5%5.5% — Chance money lasts: 50.35%5.5%6% — Chance money lasts: 40.55%6%
Show the working
  1. Withdrawal rate = $50,000 ÷ $1,250,000 = 4.00%
  2. 2,000 simulations × 40 years; each year: balance = (balance − withdrawal) × (1 + random real return)
  3. Portfolio return = 80% × stocks (mean 7.0%, sd 17.0%) + 20% × bonds (mean 2.0%, sd 7.0%)
  4. Money lasted in 1,617 of 2,000 simulations

Runs entirely in your browser. Nothing you enter is uploaded.

Formula

Withdrawal rate = first-year withdrawal ÷ starting portfolioEach simulated year: balance = (balance − withdrawal) × (1 + real return)Success rate = simulations that never run out ÷ 2,000

How it works

A safe withdrawal rate is the share of your portfolio you can spend in the first year of retirement — then keep spending, adjusted for inflation — without running out of money. The famous answer is 4% for 30 years, but the right number for you depends on how long you will be retired, how your money is invested, and how much risk you can accept.

This calculator runs a Monte Carlo simulation. It generates 2,000 different 40-year (or however long you choose) market histories, with yearly stock and bond returns drawn at random around the averages you set, and plays your retirement out in each one. The share that never runs out is your success rate.

Everything is in today's dollars: returns are real (after inflation) and your withdrawal stays the same in real terms. The simulation uses a fixed random seed, so the same inputs always give the same answer and you can compare scenarios fairly.

Why early retirees need a lower withdrawal rate

The original 4% research looked at 30-year retirements. Stretching the horizon to 40–60 years means more chances to hit a bad stretch of markets and less margin to recover. Try changing "Years in retirement" from 30 to 50 and watch the 95% safe rate fall.

The biggest danger is sequence-of-returns risk: a crash in the first few years of retirement, when you are withdrawing from a portfolio that has just fallen, does far more damage than the same crash 20 years later. That is why the bad-case line on the chart can fall away quickly even when average returns look fine.

Limitations of this simulation

Returns are drawn independently each year from a normal distribution. Real markets have fat tails, long periods of high valuations followed by poor returns, and stock-bond correlations that change over time. Historical backtests, such as those in the Trinity study and the Early Retirement Now series, capture some of these effects. Use this tool to compare scenarios and set a cautious margin, not as a guarantee.

Frequently asked questions

Is the 4% rule still safe?

For a 30-year retirement with a stock-heavy portfolio, 4% has historically worked in the large majority of periods. For 40+ year retirements, or if you expect below-average returns, 3.25–3.75% gives a more comfortable margin.

What success rate should I aim for?

Many planners target 85–95%. A 100% target forces you to spend very little in exchange for protection against the very worst cases. Being willing to trim spending in bad years lets you accept a lower simulated success rate.

Why do my results differ from FIRECalc or cFIREsim?

Those tools replay actual historical market sequences, while this one simulates random markets around average returns. Each approach has strengths; if they broadly agree, you can be more confident in your plan.

Does this include Social Security or fees?

No. To include fees, lower the expected returns by your fund expense ratio. To include later income such as Social Security, reduce your withdrawal by a portion of it, or run separate scenarios before and after benefits start.

Sources

  • Bengen, W. P. (1994). "Determining Withdrawal Rates Using Historical Data." Journal of Financial Planning.
  • Cooley, Hubbard & Walz (1998). "Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable." AAII Journal (the "Trinity study").
  • Early Retirement Now — Safe Withdrawal Rate Series
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