Retirement Withdrawal Calculator

Annual Withdrawal

Monthly Equivalent

Portfolio Longevity

Where the 4% Rule Comes From

The 4% rule is based on historical research (most famously the "Trinity Study") examining how various withdrawal rates, applied to a diversified stock-and-bond portfolio, would have performed across many historical 30-year periods. A 4% initial withdrawal rate, adjusted annually for inflation, survived the vast majority of historical 30-year periods tested without depleting the portfolio, which is why it became a widely cited reference point for retirement planning.

Why Withdrawal Rate vs. Return Matters

Whether a portfolio grows, shrinks, or stays flat over time depends on the relationship between your withdrawal rate and your actual investment return. A withdrawal rate meaningfully below your average return allows the portfolio to potentially grow even while funding withdrawals; a withdrawal rate above your average return draws down the principal, and how quickly depends on how large that gap is. This is a simplified view (it ignores the sequence of returns), but it captures the core mechanic.

Why It's a Guideline, Not a Guarantee

The 4% rule is derived from historical data, and there's no guarantee future market returns will match historical patterns closely enough for the same rate to hold. Many planners today treat 3.5% to 4% as a reasonable planning range rather than a fixed number, and recommend revisiting the withdrawal rate periodically based on actual portfolio performance rather than rigidly following the original percentage for three decades regardless of how markets perform.

Sequence-of-Returns Risk

The order in which returns occur matters as much as the average return itself, especially in the years right after retirement begins. A market downturn early in retirement, combined with ongoing withdrawals, can permanently impair a portfolio's ability to recover, because withdrawals during a down market lock in losses on shares sold at depressed prices. This is why some retirees keep a cash buffer or shift to a more conservative allocation heading into retirement, specifically to reduce this early-sequence risk.

Frequently Asked Questions (FAQ)

1. What is the 4% rule?

The 4% rule suggests withdrawing 4% of your retirement portfolio in the first year, then adjusting that dollar amount for inflation each subsequent year, based on historical research into how often that approach avoided depleting a portfolio over a 30-year retirement.

2. Is the 4% rule guaranteed to work?

No. It's a historically-derived guideline, not a guarantee, since future market returns may not mirror the historical data the rule was built on. Many planners treat 3.5-4% as a reasonable range and recommend revisiting the withdrawal rate periodically.

3. How long will my portfolio last at a given withdrawal rate?

It depends on your withdrawal rate versus your portfolio's investment return; a withdrawal rate below your average return can sustain a portfolio indefinitely, while higher withdrawal rates draw down the principal over time.

For official Social Security guidance, see the Social Security Administration's retirement resources. Project your accumulation phase with the Retirement Corpus Calculator.