Once you have reached your FIRE number, the next challenge is determining how to spend that money without running out. This is where the 4% Rule comes into play. While the Rule of 25 tells you how much to save, the 4% Rule tells you how much you can safely withdraw each year to sustain a retirement that could last decades.

The Mechanics of the 4% Rule

The 4% Rule states that a retiree can withdraw 4% of their total investment portfolio in the first year of retirement . In every subsequent year, the retiree adjusts that initial dollar amount for inflation to maintain their standard of living .

Step-by-Step Withdrawal Process:

Year 1: You have $1,000,000. You withdraw 4%, which is $40,000.
Year 2: Inflation was 3%. You don't take 4% of the new balance; instead, you take the previous year's $40,000 and add 3%. Your new withdrawal is $41,200.
Year 3 and Beyond: You continue to adjust the previous year's withdrawal amount by the inflation rate, regardless of whether the stock market went up or down that year.

The Origins and Assumptions of the Rule

The 4% Rule is based on historical market data and was originally designed to ensure a portfolio would last for at least 30 years . It assumes a balanced portfolio of stocks and bonds that can weather various economic cycles. However, for the FIRE movement, where retirement might last 40, 50, or even 60 years, the 4% Rule requires careful scrutiny.

The 30-Year Limitation

Because the 4% rule assumes a 30-year goal, it may not be sufficient for someone retiring at age 35 or 40 . If you plan to be retired for more than three decades, many experts suggest a more conservative withdrawal rate, such as 3.5% or even 3%, to account for the longer timeframe and the increased risk of "sequence of returns" (the risk of a market crash happening right after you retire).

Managing the "Gap Years" and Tax Efficiency

A unique challenge for FIRE followers is the period between their early retirement age and age 59½, which is when most tax-advantaged retirement accounts (like Traditional IRAs and 401(k)s) allow for penalty-free withdrawals .

The Strategy for Early Access:

Brokerage Accounts: These are "regular" investing accounts with no withdrawal age limits. FIRE followers often save enough in these accounts to cover the years between retirement and age 59½ .
Roth IRA Contributions: You can always withdraw your contributions (but not earnings) from a Roth IRA tax- and penalty-free at any time.
Roth Conversion Ladders: This involves moving money from a Traditional IRA to a Roth IRA. After five years, these converted funds can often be accessed penalty-free .
The Cost of Taxes: While you can't avoid taxes entirely, being strategic about which accounts you pull from can minimize the "tax drag" on your portfolio. As Rachael Burns notes, "If you're paying taxes, it probably means you're making money. So it's kind of a good thing" .

Risks to the 4% Rule

The 4% Rule is a "rule of thumb" and a "big generalization" . It is not a guarantee. Several factors can put your portfolio at risk:

Market Turmoil: If the market drops significantly in your first few years of retirement, withdrawing 4% (plus inflation) can deplete your principal too quickly. FIRE requires you to stay invested even during turmoil and potentially "adjust spending or saving in certain years based on market events" .
Underperformance: If your investments don't achieve the expected returns (e.g., a 5% post-retirement rate of return), the math fails .
Healthcare Costs: Until Medicare kicks in at age 65, you must foot your own medical expenses, which can be a massive, unpredictable variable in your budget .

Comparison: Withdrawal Rates and Portfolio Longevity

Withdrawal Rate	Initial Annual Income (on $1M)	Risk Level for 40+ Year Retirement
3.0%	$30,000	Very Low / Conservative
3.5%	$35,000	Low / Moderate
4.0%	$40,000	Moderate (Standard for 30 years)
4.5%	$45,000	High / Aggressive
5.0%	$50,000	Very High / Risky

FAQ: Safe Withdrawals

Q: Should I still use the 4% rule if the market is crashing?
A: Flexibility is key. Many FIRE adherents use "variable withdrawal rates," meaning they might cut their spending to 3% during a bad market year and go back to 4% when the market recovers .

Q: Does the 4% rule account for investment fees?
A: Usually, no. If your mutual funds or advisors charge high fees, that comes out of your 4%. This is why many in the FIRE movement prefer low-cost index funds and ETFs to keep more of their money working for them .

Q: What is a "conservative" rate of return?
A: For planning purposes, a 6% pre-retirement return and a 5% post-retirement return are considered conservative estimates, even though the stock market has historically averaged closer to 10% .