What the 4% Rule Assumes—and What Changes in Early Retirement

The 4% rule is a historical starting-withdrawal framework, not a guaranteed yield and not an instruction to withdraw 4% of the current balance every year.

By Steven, Founder · Published November 11, 2026 · Updated November 11, 2026

Short answer

The classic method starts with a percentage of the initial portfolio, then adjusts the dollar withdrawal for inflation.
Historical survival over a roughly 30-year target is not a guarantee for a longer future retirement.
Taxes, fees, allocation and spending flexibility change what the rule means for a household.

What the original research actually tested

William Bengen's 1994 paper examined historical U.S. stock and intermediate-term Treasury returns with inflation-adjusted withdrawals. Its initial illustrations used a rebalanced 50/50 stock/bond portfolio; it also studied other allocations. The familiar 4% starting figure came from seeking at least 30 years of portfolio longevity across those historical scenarios.

That is narrower than 'all portfolios can pay 4% forever.' It is historical evidence under specified data, assets and withdrawal rules. It does not establish future returns, a household's tax bill, or the safety of holding a different asset mix at different costs.

The second-year dollar amount explains the rule

With a $1 million starting portfolio, a 4% first-year withdrawal is $40,000. If inflation is 3%, the following year's withdrawal is $41,200 under the constant-real-spending method, regardless of whether the portfolio has risen or fallen.

If the balance just before that second withdrawal is $800,000, taking 4% of the current balance would instead produce $32,000. That is a different strategy with lower spending after losses. It can reduce depletion pressure, but it does not maintain the same purchasing power. Do not compare the strategies as if their spending promises were identical.

Early retirement lengthens exposure

Retiring at 45 and planning to 95 creates a 50-year horizon; retiring at 65 with the same endpoint creates 30 years. A rate studied for a shorter interval cannot simply inherit the same historical result over the longer interval. Longer plans also have more opportunities for expenses, tax law and household circumstances to change.

Bengen's paper itself explored lower starting withdrawals and longer horizons. That does not turn another percentage into a universal answer. Use the withdrawal calculator to see horizon sensitivity, then test return sequences rather than assuming a smooth average validates the rate.

A portfolio withdrawal is not all available spending

If $40,000 is withdrawn from a fully taxable account, some may go to tax. If taxes and fees must be paid from the portfolio, they consume resources too. Conversely, Social Security, pensions or part-time earnings can reduce the portfolio's required draw once they start.

Do not apply a withdrawal rate to total net worth that includes an unmonetized home. Use assets actually available to fund the spending plan. For early retirees, also check access rules: a sustainable-looking pretax balance does not automatically create penalty-free cash before 59½.

Write down a spending policy

Decide which dollars are essential, which purchases can move, and what change you would make after a poor market start. A policy that trims travel by a stated amount is testable. An assumption that you can cut all spending whenever necessary may conceal a lifestyle you would not accept.

Read the money-lasts guide and explore the sample household demo to connect withdrawals to actual income phases. These educational frameworks describe tradeoffs, not a personalized safe-withdrawal recommendation.

Inflation-adjusted dollars versus a current-balance percentage

Starting portfolio / initial draw: $1,000,000 / $40,000
Inflation: 3%
Next-year portfolio before draw: $800,000

$41,200 constant-real draw versus $32,000 at 4% of current assets

The first method multiplies last year's dollars by 1.03; the second multiplies the current portfolio by 0.04. Their spending outcomes differ by $9,200.

Related free calculators

Methodology

See how Meridary checks calculator figures, tests the planning engine, states model limits, and records corrections on the validation methodology page.

Sources

Determining Withdrawal Rates Using Historical Data (1994; 2004 reprint) — William P. Bengen, Journal of Financial Planning / Financial Planning Association
Historical U.S. stock/Treasury retirement tests, initial-balance withdrawal percentages followed by inflation adjustments, rebalancing, and the inadequacy of average returns for drawdown planning.
Accessed October 25, 2026
Retirement topics: Exceptions to tax on early distributions — Internal Revenue Service
The separation-from-service exception applies to qualified plans, not IRAs, in or after the calendar year the employee reaches 55; penalty exceptions do not eliminate ordinary income tax.
Accessed October 25, 2026

This is an educational estimate, not tax or financial advice. Figures reflect the law year shown and the inputs you provide. Consult a qualified professional before acting.