The 4% Rule: Your Guide to Safe Withdrawal Rates

What Is the 4% Rule?

The 4% rule is the most famous concept in the FIRE community. It states that you can safely withdraw 4% of your portfolio in the first year of retirement, then adjust that amount for inflation each subsequent year, and have a high probability of not running out of money over a 30-year period.

The Trinity Study

The 4% rule comes from the Trinity Study (1998), conducted by three professors at Trinity University. They analyzed historical stock and bond returns from 1926 to 1995 to determine "safe withdrawal rates" for retirees.

Key findings:

• A 4% withdrawal rate had a 95% success rate over 30-year periods
• Success was higher with a portfolio of 50-75% stocks
• Lower withdrawal rates (3-4%) were significantly safer than higher ones (5-7%)

How to Calculate Your FIRE Number

The math is straightforward:

FIRE Number = Annual Expenses ÷ Withdrawal Rate

Using the 4% rule:

FIRE Number = Annual Expenses ÷ 0.04
FIRE Number = Annual Expenses × 25

Examples

Annual Expenses	Withdrawal Rate	FIRE Number
$30,000	4%	$750,000
$50,000	4%	$1,250,000
$80,000	4%	$2,000,000
$100,000	4%	$2,500,000

Is 4% Still Safe?

The debate continues in the FIRE community:

Arguments For 4%

• The Trinity Study used worst-case historical scenarios
• A flexible withdrawal strategy (spending less in down years) significantly improves success rates
• Social Security, part-time work, or other income sources provide a safety buffer

Arguments For a Lower Rate

• Some experts suggest 3.5% or even 3% for very early retirees (50+ year time horizons)
• Current high market valuations (CAPE ratio) may suggest lower future returns
• Healthcare costs and inflation uncertainty add risk

Practical Withdrawal Strategies

Fixed Percentage

Withdraw the same inflation-adjusted amount each year. Simple but rigid.

Variable Percentage Withdrawal

Adjust withdrawals based on portfolio performance. More flexible, better success rates.

Guardrails Approach

Set upper and lower spending limits. Increase spending when the market is up, cut back when it's down.

Our Recommendation

For early retirees (40+ year horizon), we recommend:

• Target a 3.5% initial withdrawal rate for extra safety
• Use a variable withdrawal strategy with spending flexibility
• Maintain a 75% stock / 25% bond portfolio during retirement
• Re-evaluate annually

Use our 4% Rule Calculator to model your personal FIRE scenario.