Does the FIRE Movement Overestimate How Much You Need to Retire?

Quick Answer

For most people, yes. The standard FIRE formula of 25 times your annual expenses ignores Social Security, assumes your spending never changes, and is calibrated to survive the worst 30-year stretch in market history. Your actual number is probably lower. But there are scenarios where it might not be enough.

The 25x Rule and Where It Came From

The math is simple. Take your annual expenses. Multiply by 25. That is your FIRE number. It comes from the 4% rule, which says you can withdraw 4% of your portfolio each year without running out of money over 30 years.

Spend $40,000 a year? You need $1,000,000. Spend $80,000? You need $2,000,000.

The number comes from the Trinity Study, which tested historical withdrawal rates across every 30-year period from 1926 to 1995. The 4% rate survived them all, including the Great Depression and the stagflation of the 1970s.

The problem is that people treat this worst-case floor as a target. It is like packing for Antarctica when you are going to Denver. You will be warm. But you will also be carrying a lot of unnecessary weight.

Three Reasons the Number Is Probably Too High

Social Security Exists

The 25x calculation assumes your portfolio covers everything. But if you are an American who has worked for ten or more years, you will receive Social Security. The average benefit is roughly $22,000 per year. For a couple, that is $44,000.

If you spend $60,000 a year and expect $30,000 from Social Security, your portfolio only needs to cover $30,000. Your FIRE number drops from $1,500,000 to $750,000. That is a massive difference. Most FIRE calculators online ignore this completely. Ours does not.

Spending Decreases With Age

Study after study shows that retirees spend less as they age. The Bureau of Labor Statistics data is clear: spending peaks between ages 45 and 54, then drops steadily. By 75, most people spend 20% to 30% less than they did at 55.

The early retirement years are the expensive ones. Travel, hobbies, projects. By 70, most people have settled into a lower-cost routine. The 25x rule assumes constant spending forever. Reality is more forgiving.

You Will Probably Earn Something

Most early retirees do not sit on the couch for 40 years. They consult. They teach. They start small businesses. They work part-time at jobs they enjoy. Even $15,000 a year in casual income reduces your required withdrawal rate by a full percentage point or more.

JL Collins calls this "FU money." Once you have enough to walk away from work you hate, you are free to do work you love, often for money. That income, even if modest, can add a decade or more to your portfolio's life.

When 25x Might Not Be Enough

Healthcare: The Wild Card

If you retire before 65 in the United States, you need to buy health insurance on the open market. This can cost $500 to $1,500 per month for a single person, more for a family. ACA subsidies help if your income is low enough, but you need to manage your withdrawals carefully to qualify. Pull too much in one year and the subsidy vanishes.

After 65, Medicare helps, but it is not free. Premiums, deductibles, co-pays, and supplemental coverage (Medigap or Advantage plans) can run $3,000 to $8,000 per year per person. And none of this covers long-term care, which averages over $100,000 per year for a nursing home. Healthcare is the one expense that increases faster than inflation and cannot be easily cut. Add a specific line item for it. Do not hope your general budget absorbs it.

Sequence of Returns Risk

The 25x rule assumes average returns. But averages hide the order. A 30% crash in your first year of retirement, combined with withdrawals, can permanently damage a portfolio even if the long-term average is fine. This is sequence of returns risk, and it is the biggest mathematical threat to early retirees. A cash buffer and spending flexibility are your primary defenses.

Inflation Surprises

The 4% rule accounts for historical inflation. But the period from 2021 to 2023 reminded everyone that inflation can spike fast. If your fixed expenses are a large percentage of your budget, a year of 8% inflation hits hard.

The defense is the same as always: keep your fixed expenses low and your flexible spending high. A retiree who spends $20,000 on rent and $40,000 on everything else has much more room to adapt than one who spends $40,000 on rent and $20,000 on everything else.

Social Security May Shrink

If you are counting on Social Security to lower your FIRE number, factor in some uncertainty. The Social Security trust fund is projected to face shortfalls by the mid-2030s. Benefits are unlikely to disappear, but reductions of 20% to 25% are possible if Congress does nothing. For a 35-year-old planning a 50-year retirement, building your plan around 75% of your projected benefit is more prudent than assuming full payment.

The Real Answer: Your Number Is Personal

The internet will tell you that you need $1 million, $2 million, or $5 million. These numbers are meaningless without context.

How much do you need to retire early? It depends on three things: what you spend, where you live, and how flexible you are willing to be.

A person who spends $30,000 a year in a low-cost city with a paid-off house needs roughly $400,000 to $500,000 above what Social Security will cover. A person who spends $120,000 a year in San Francisco with a mortgage needs $2 million or more.

Do not use someone else's number. Run your own. Input your actual expenses, your expected Social Security, your savings rate, and your expected returns. The result will be more useful than anything you read on Reddit.

As Bogle said: the greatest enemy of a good plan is the dream of a perfect plan. Get your number close enough, build in some flexibility, and go live your life.

Frequently Asked Questions

Is 25x expenses really the standard FIRE target?

It is the most common rule of thumb. It maps directly to a 4% withdrawal rate (1 divided by 0.04 equals 25). Some conservative planners use 30x or 33x, which correspond to 3.3% withdrawal rates. The right multiple depends on how long your retirement will last and how flexible your spending is.

What if I retire at 35 instead of 55?

A longer retirement means more time for things to go wrong. For a 50-year or 60-year retirement, most studies suggest a withdrawal rate between 3.3% and 3.8%, which means you need 26x to 30x expenses. But remember: this still ignores Social Security, future income, and spending flexibility, all of which work in your favor.

Should I include my house in my FIRE number?

No. Your house does not generate income unless you sell it or rent it out. Include only liquid investments you can actually withdraw from: brokerage accounts, IRAs, 401(k)s. Your paid-off house reduces your expenses, which reduces your FIRE number. That is how it helps.

What is a good savings rate for FIRE?

A 50% savings rate will get you to financial independence in roughly 17 years from zero. A 25% savings rate takes about 32 years. The math is not linear because compound growth accelerates over time. The savings rate matters most in the first decade. After that, your returns start doing the heavy lifting.

Sources

• Cooley, Philip L., Carl M. Hubbard, and Daniel T. Walz. "Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable" (Trinity Study). AAII Journal, February 1998.
• Bureau of Labor Statistics. Consumer Expenditure Surveys, 2022. Spending by age group data showing decline after age 55.
• Social Security Administration. 2024 Annual Report of the Board of Trustees. Trust fund depletion projections and benefit reduction estimates.
• Genworth Financial. Cost of Care Survey, 2023. National median nursing home costs exceeding $100,000 per year.
• Collins, JL. The Simple Path to Wealth. 2016. FIRE planning philosophy and the role of earned income in early retirement.