FIRE (Financial Independence, Retire Early)

FIRE, short for Financial Independence, Retire Early, is a personal finance movement whose followers save and invest a large share of their income so that the returns from their investments can cover living costs. Once that point, called financial independence, is reached, paid work becomes optional, often decades before the usual retirement age of the mid-sixties.

The movement is informal: it has no founder or governing body, and it spreads mainly through books, blogs, podcasts and online forums. It grew out of the ideas in Your Money or Your Life by Vicki Robin and Joe Dominguez (1992), which asked readers to measure purchases in hours of life spent earning them, and became widely known in the 2010s through bloggers such as Mr. Money Mustache. Its maths rests on research into safe withdrawal rates from retirement savings.

Imagine a fruit tree. Each year you can eat the fruit and leave the tree standing. FIRE followers try to plant and grow a tree big enough that its fruit alone feeds them, so they never need to cut it down or go out to buy food. The tree is a pile of investments; the fruit is the return it pays each year.

Growing the tree quickly means two things: spending less, so there is more to plant, and keeping living costs low, so a smaller tree is enough. That is why FIRE writing focuses as much on frugal living as on investing.

The central figure in FIRE planning is the "FI number", the size of portfolio needed to cover annual spending indefinitely. It is calculated as:

Here annual spending is what the household expects to spend each year after it stops working, and the safe withdrawal rate is the share of the portfolio it plans to withdraw each year. Most followers use 4%, which gives the rule of thumb of saving 25 times annual spending, because $1 \div 0.04 = 25$.

For example, a household that expects to spend $40,000 a year needs $40{,}000 \div 0.04 = 1{,}000{,}000$, or $1 million. In the first year it withdraws $40,000 and in later years raises the withdrawal in line with inflation.

The 4% figure comes from a 1994 study by the financial planner William Bengen, who found that, using US market history, a retiree with a mix of shares and bonds could withdraw 4% of the starting balance, adjusted for inflation, without running out of money over 30 years. A 1998 paper by three professors at Trinity University, known as the Trinity study, reached similar conclusions. Because early retirees may need their money for 40 years or more, many FIRE writers prefer a lower rate, such as 3% to 3.5%.

• High savings rate. Followers often save 50% or more of take-home pay, far above typical household rates. The higher the savings rate, the fewer years to independence.
• Low-cost investing. Savings usually go into broad, low-fee index funds or exchange-traded funds, relying on long-term market growth and compound interest.
• Tax-advantaged accounts. Retirement accounts that defer or reduce taxes are used heavily, with planning for how to access them before the normal age.
• Cutting costs and debt. Paying off high-interest debt, living in cheaper areas and limiting car and housing costs keep the FI number low.
• Extra income. Side businesses, freelancing, work in the gig economy and rental property add to passive income.

The movement has several named versions, which differ mainly in the target spending level:

• Lean FIRE. Independence on a very modest budget, accepting a frugal lifestyle.
• Fat FIRE. Saving enough to retire with a comfortable or high level of spending.
• Barista FIRE. Leaving a main career while keeping part-time work that covers some costs or provides health insurance.
• Coast FIRE. Saving enough early that the portfolio will grow to the FI number by normal retirement age without further contributions, so the person only needs to earn current living costs.

Some followers combine early retirement with moving abroad to lower-cost countries, overlapping with the digital nomad lifestyle.

Critics point out that very high savings rates are only realistic for people with high incomes, low fixed costs or no dependants. The historical data behind the 4% rule come mostly from US markets, which performed unusually well in the twentieth century; a poor run of returns in the first years of retirement, known as sequence-of-returns risk, can deplete a portfolio quickly. Health-care costs, rising interest rates and changes to state pensions such as Social Security add uncertainty. Others argue that the extreme frugality required can harm quality of life, and that many "retired" followers in fact keep earning from blogs or part-time work. Supporters reply that even partial progress builds net worth and choice, can become generational wealth, and that the movement has improved financial literacy among younger savers.