The 4% Rule Explained: Bengen / Trinity, When It Works, When It Doesn't

Where the 4% rule came from, when it survived historically, and where it breaks under longer horizons, sequence risk, and forward-looking return regimes.

Sources: Bengen (1994), Trinity Study, Guyton-Klinger guardrails.

Sustainable years · by withdrawal rate
3%4%5%6%7%8%4% rule · ~35 yrsBengen / Trinity historical reference

Illustrative — based on historical-data sustainability at 60/40 mix. Real outcomes vary with sequence risk.

Last updated: February 14, 2026

What Is the 4% Rule?

The 4% rule is a widely cited rule of thumb for retirement withdrawals. It says: in your first year of retirement, withdraw 4% of your portfolio. In each following year, withdraw that same dollar amount adjusted for inflation. Historically, this approach allowed portfolios to last at least 30 years in most past market conditions.

Example: With $1,000,000 saved, you would withdraw $40,000 in year one. If inflation is 3%, in year two you would withdraw $41,200, and so on.

Where It Came From

The idea is often attributed to William Bengen and his 1994 research using U.S. historical data. He found that a 4% initial withdrawal rate, increased each year for inflation, survived 30-year retirements in the past. Later, the "Trinity Study" and others reinforced that similar withdrawal rates could work for balanced portfolios over many decades.

When the 4% Rule Works

  • You have a diversified portfolio (e.g. mix of stocks and bonds)
  • You plan for a "typical" 30-year retirement
  • You can accept that it was validated on past data, not a guarantee for the future
  • You want a simple, easy-to-remember starting point

Limitations

The 4% rule is a starting point, not a guarantee. Important limitations include:

  • Sequence of returns risk: Poor returns early in retirement can hurt outcomes even if long-run averages look good.
  • Historical data: Past U.S. returns may not repeat; today's valuations and interest rates differ.
  • Taxes and expenses: The rule doesn't model taxes, healthcare, or changing spending.
  • One size doesn't fit all: Your lifespan, risk tolerance, and goals may call for a different rate or strategy.

Many planners now use 3–3.5% for extra safety or pair the idea with dynamic strategies that adjust spending when the portfolio or markets change.

Alternatives: Dynamic Withdrawal Strategies

Dynamic strategies adjust withdrawals based on portfolio performance, age, or guardrails. They can improve both safety and spending flexibility compared to a fixed inflation-adjusted 4%. Praxion Finance models several approaches—including expense-based, guardrails, and hybrid methods—so you can compare them to a 4%-style rule.

Beyond the 4% Rule: Withdrawal Methodology explains our multi-objective approach. Use our Withdrawal Strategy Comparison tool to compare the 4% rule and other strategies side by side.

Learn More

Learning Center · Retirement Basics · Sequence of Returns Risk · Savings Tracker: Retirement Readiness Guide