What is FIRE? Financial independence, explained

FIRE stands for Financial Independence, Retire Early. The idea is simple, even if the journey isn't: save and invest enough that the returns on your money can cover your living costs. When that happens, work becomes a choice instead of a must. Here's the whole picture — the idea, the two numbers that drive it, and how to get started.

The idea in one sentence

Build a pot of invested money big enough that it pays your bills for you.

That's it. You're not trying to get rich for the sake of it. You're buying back your time. Some people quit work entirely. Most use FIRE to take a lower-paid job they love, go part-time, or just sleep better knowing they could walk away. "Retire early" is the headline, but "financial independence" is the real prize.

The two numbers that matter

Almost everything in FIRE comes down to two numbers.

Your FIRE number is roughly 25 times your annual spending. Spend $40,000 a year? Your target is about $1,000,000. This comes from the 4% rule: historically, you could withdraw about 4% of a diversified portfolio in year one and adjust for inflation each year after, and the money lasted for decades. Flip 4% around and you get 25×. Notice it's built on your spending, not your income — which is why cutting costs shrinks the target twice over. Work out yours with the FIRE calculator.

Your savings rate is the share of your take-home pay you keep and invest. This is the single biggest lever you have — bigger than picking the perfect fund. At a 10% savings rate, FIRE takes a lifetime. At 50%, it takes something like 17 years, whatever your salary. Check yours with the savings rate calculator and dig into it under saving.

Why it actually works: compounding

FIRE isn't magic. It's compound interest doing the heavy lifting over time — your returns earning returns of their own.

The chart shows why starting early beats starting big. The early years feel slow and boring. Then the curve bends upward, and eventually your portfolio's yearly growth can dwarf what you add yourself. Your job is to feed it consistently and not panic when markets wobble. Most people do this with low-cost index funds — see investing.

The flavours of FIRE

FIRE isn't one-size-fits-all. A few common variants:

• Lean FIRE — a smaller number, funding a deliberately frugal life.
• Fat FIRE — a bigger number, so you retire on a comfortable, roomy budget.
• Coast FIRE — you invest enough early that, left alone, it grows to your target by traditional retirement age. After that you only need to cover today's costs.
• Barista FIRE — you're most of the way there, then a part-time or lighter job bridges the rest.

None is more "correct" than another. They're just different points on the same line.

How to start

You don't need a perfect plan to begin. You need momentum.

1. Learn the idea — you're doing that now.
2. Find your number with the FIRE calculator.
3. Raise your savings rate, even a little — start with saving.
4. Invest simply and cheaply in broad index funds.
5. Stay the course. The lifestyle you build along the way is the point.

New here? Begin with the start-here path, and lean on the tools — your own numbers say more than any article.