What is FIRE? Financial independence, retire early

FIRE stands for Financial Independence, Retire Early. Financial independence means your investments can pay for your life indefinitely, so a paycheck becomes optional. "Retire early" is what many people do with that freedom, but plenty keep working on their own terms: part-time, on a passion project, or at the same job without the fear of losing it.

How FIRE works

The whole idea fits in three steps:

1. Spend well below what you earn. The gap between income and spending, your savings rate, is the engine. Most people pursuing FIRE save 30% to 70% of their take-home pay.
2. Invest the difference, usually in low-cost, broadly diversified index funds held in tax-advantaged accounts first.
3. Stop when your portfolio reaches about 25 times your annual spending. That is your FI number. At that size, withdrawing 4% a year, adjusted for inflation, has historically lasted at least 30 years in almost every market period.

Someone who spends $40,000 a year needs roughly $1,000,000 invested. Someone who spends $60,000 needs about $1.5 million. Notice that the target depends on what you spend, not what you earn. That's why cutting spending works twice: it raises how much you save each year and lowers the amount you need.

Where FIRE came from

The movement traces back to the 1992 book Your Money or Your Life by Vicki Robin and Joe Dominguez, which reframed money as "life energy" you trade your hours for. It took off online in the 2010s through blogs like Mr. Money Mustache and Early Retirement Extreme, and through the forums and subreddits that grew around them. The research backbone came from William Bengen's 1994 withdrawal-rate study and the 1998 Trinity study, which gave people a defensible way to say how much is enough.

The flavors of FIRE

• Lean FIRE: retiring on a frugal budget, often under $40,000 a year.
• Fat FIRE: retiring with a large cushion, often $100,000+ a year of spending.
• Coast FIRE: saving enough early that compounding alone will carry you to a normal retirement, so you only need to cover today's bills.
• Barista FIRE: leaving full-time work and covering part of your spending with part-time income.

Each is covered in Lean, Fat, Barista and Coast FIRE explained.

Is FIRE realistic?

The math is simple; the behavior is hard. At a 10% savings rate, reaching FI from zero takes about 50 years, which is a traditional retirement. At 50%, it takes about 17 years. At 70%, under 10. Higher incomes make high savings rates easier, but the biggest lever for most people is housing, transportation and food, the three largest line items in most budgets.

FIRE also carries real risks: a bad stretch of markets right after you retire (sequence-of-returns risk), health insurance before Medicare at 65, and the challenge of reaching retirement accounts before age 59½ (covered in how to access retirement money early). None of these is a dealbreaker, but each needs a plan.

Your first step

Track your spending for a month or two, then plug the annual figure into the FIRE calculator. It shows your FI number, the year you'd get there at your current savings rate, and how much each change moves the date.