How The 4% Retirement Rule Works

The 4% Rule: A Starting Point for Retirement Withdrawals
After spending decades accumulating retirement savings, retirees face a new challenge: determining how much they can reasonably withdraw and spend.

Withdraw too much, particularly during the early years, and the portfolio may be depleted faster than expected. Withdraw too little, and the retiree may unnecessarily limit the lifestyle the savings were intended to support.

The 4% rule provides a simple starting point for this decision. Although widely used, it is not a guarantee or a complete retirement-income plan.

How the 4% Rule Works
The rule begins with a withdrawal equal to 4% of the investment portfolio during the first year of retirement.

The dollar amount—not 4% of each subsequent year’s balance—is then adjusted annually for inflation.

For example, consider a retiree with a $1 million portfolio:

• First-year withdrawal: $40,000
  
• Assumed first-year inflation: 2%
  
• Second-year withdrawal: $40,800
  

If inflation were 3% during the following year, the third-year withdrawal would increase by another 3%.

This approach attempts to maintain the retiree’s purchasing power while providing a disciplined withdrawal framework.

It should not be confused with withdrawing 4% of the remaining portfolio every year. That method would produce income that rises and falls with the account balance, while the traditional rule seeks to produce inflation-adjusted spending.

Where Did the Rule Come From?
Financial planner William Bengen introduced the research underlying the rule in 1994.

Bengen studied historical U.S. stock and bond returns across different retirement periods. His objective was to identify a starting withdrawal rate that could support inflation-adjusted spending through difficult historical market environments.

The original work used specific assumptions involving historical returns, retirement length, asset allocation, and annual inflation adjustments. It was not a conclusion that every retiree can always withdraw 4% without risk.

The research remains influential because it illustrates an important principle: retirement outcomes depend not only on average returns, but also on when favorable and unfavorable returns occur.

Read Bengen’s published research through the Financial Planning Association

Why the Rule Is Useful
The 4% rule remains popular because it is easy to understand and apply.

It can help prospective retirees:

• Estimate the portfolio needed to support a spending target
  
• Establish an initial withdrawal framework
  
• Avoid excessive spending early in retirement
  
• Compare current savings with expected expenses
• Begin a more detailed retirement-income analysis
  

For example, someone seeking $120,000 of annual portfolio withdrawals could divide that amount by 4%, producing a preliminary portfolio target of $3 million.

That calculation is useful as a rough estimate, but it excludes taxes, Social Security, pensions, healthcare costs, investment fees, and other important variables.

The result should therefore begin the planning conversation—not end it.

Where the 4% Rule Can Fall Short
The rule applies one standardized framework to retirees whose circumstances may differ substantially.

Retirement length
The original framework is commonly associated with a 30-year retirement.

Someone retiring at 50 or 55 may need the portfolio to provide income for considerably longer. A longer time horizon generally increases the uncertainty surrounding inflation, returns, healthcare costs, and longevity.

Conversely, an older retiree or someone with substantial lifetime income from other sources may have different spending capacity.

Asset allocation
Withdrawal sustainability depends partly on how the portfolio is invested.

A portfolio concentrated in stocks may experience significant volatility, while an overly conservative portfolio may struggle to keep pace with inflation over a long retirement. The original research was based on particular combinations of U.S. stocks and bonds—not cash, private investments, concentrated stock, or every possible allocation.

A withdrawal rate cannot be evaluated separately from the investments supporting it.

Sequence-of-returns risk
Poor investment returns during the first several years of retirement can be especially damaging.

When withdrawals are made while a portfolio is declining, more assets must be sold to generate the same income. That leaves fewer assets available to participate in a subsequent recovery.

Two retirees can earn the same average return over 30 years and experience very different outcomes because the returns occurred in a different order.

Taxes
A $40,000 withdrawal does not necessarily provide $40,000 of spendable income.

Traditional retirement-account distributions may be taxed as ordinary income. A taxable brokerage withdrawal may consist of principal and capital gains. Qualified Roth withdrawals generally receive different tax treatment.

The source of each withdrawal can therefore affect how much the retiree retains after taxes.

Changing spending
The traditional rule assumes that withdrawals rise with inflation each year. Actual retirement spending is rarely that consistent.

Many retirees spend more on travel and experiences early in retirement. Discretionary spending may decline later, while healthcare, support, or long-term-care expenses could rise.

A personalized plan should reflect these anticipated phases instead of assuming one unchanging spending pattern.

Unexpected obligations
Family support, home repairs, second properties, charitable gifts, and major healthcare expenses can all increase withdrawals beyond the original plan.

A retirement strategy needs room for irregular expenses—not only predictable monthly spending.

Should the Starting Rate Be Higher or Lower?
There is no universally correct withdrawal rate.

A lower starting rate may be appropriate when a retiree has:

• A retirement expected to last longer than 30 years
  
• Limited flexibility to reduce spending
  
• A concentrated or volatile portfolio
  
• Significant future healthcare concerns
  
• A strong desire to leave a legacy
  
• Few sources of income outside the portfolio
  

A higher starting rate might be considered when the retiree has a shorter planning horizon, meaningful pension or Social Security income, substantial spending flexibility, or assets well beyond anticipated lifetime needs.

That does not make a higher withdrawal rate “safe.” It means the retiree may have more capacity to accept the associated risk.

A Flexible Strategy May Be More Practical
Retirement spending does not have to operate on autopilot.

A flexible approach may begin with a target withdrawal and establish guidelines for making adjustments. For example, a retiree might:

• Limit inflation increases after a poor market year
  
• Reduce discretionary spending during an extended decline
  
• Increase spending when the portfolio materially exceeds projections
  
• Maintain separate reserves for near-term expenses
  
• Revisit the withdrawal plan after major tax or family changes
  

This allows the strategy to respond to actual market results rather than assuming the original projection will unfold exactly as expected.

Use 4% as a Baseline, Not a Promise
The 4% rule can provide a useful first estimate of what a diversified portfolio might support. Its strength is simplicity, but that is also its limitation.

A complete retirement-income plan should incorporate:

• Expected retirement length
  
• Lifestyle spending
  
• Social Security and pensions
  
• Account types and taxes
  
• Investment allocation
  
• Inflation
  
• Healthcare and long-term care
  
• Legacy and charitable objectives
  
• The ability to adjust spending
  

Tidecrest Wealth Management helps families coordinate these variables within a retirement strategy built around their specific circumstances.

If you are preparing for retirement and want to understand what your portfolio may sustainably support, we invite you to schedule a conversation with our team.

This material is provided for educational purposes only and should not be considered individualized investment, tax, or legal advice. The 4% rule is based on historical research and specific assumptions that may not reflect future results or an individual investor’s circumstances. No withdrawal strategy can guarantee that assets will last throughout retirement. Investing involves risk, including possible loss of principal.