Coast FIRE vs Lean FIRE vs Fat FIRE

The Three Paths to Financial Independence

FIRE (Financial Independence, Retire Early) is not one-size-fits-all. The movement has splintered into distinct strategies, each with different target numbers, timelines, and lifestyle trade-offs. Understanding the differences helps you pick a realistic path rather than chasing a number that doesn't match how you actually want to live.

Coast FIRE

Coast FIRE is the milestone where your existing investments, left untouched, will compound to a full retirement portfolio by a traditional retirement age (typically 65). Once you reach this point, you no longer need to save for retirement at all. You still work, but only enough to cover current expenses. Many Coast FIRE practitioners downshift to part-time, freelance, or passion work.

Lean FIRE

Lean FIRE means achieving full financial independence on a minimized budget, typically $25,000 to $40,000 per year in spending. You can walk away from work entirely, but you commit to a frugal lifestyle indefinitely. Geographic arbitrage (living in low-cost areas or abroad) is a common Lean FIRE strategy.

Fat FIRE

Fat FIRE is full financial independence with no spending compromises. You maintain (or exceed) your current lifestyle in retirement, typically targeting $100,000 to $200,000+ per year in spending. This path requires either high income, a long accumulation period, or both.

Which Path Should You Choose?

Real-World Example: Three Paths for the Same Person

Try the Calculators

What is Coast FIRE and how does it work?

Coast FIRE means you have saved enough early in life that compound growth alone will carry your portfolio to a full retirement number by age 65. Once you hit Coast FIRE, you only need to earn enough to cover current living expenses and no longer need to save for retirement.

How much do I need for Lean FIRE vs Fat FIRE?

Lean FIRE typically requires 25x your minimized annual spending, usually $625,000 to $1,000,000 based on $25,000 to $40,000 per year in expenses. Fat FIRE requires 25x a more comfortable spending level, often $2,500,000 to $5,000,000+ based on $100,000 to $200,000 per year in expenses.

Can I switch between FIRE strategies?

Absolutely. Many people start by targeting Lean FIRE for a quick exit, then continue working toward Fat FIRE once they have the security of a lean number. Coast FIRE can serve as a milestone on the way to either goal.

Is Lean FIRE risky because the budget is so tight?

Yes, Lean FIRE carries more risk. A tight budget leaves little room for unexpected medical bills, home repairs, or inflation spikes. Most Lean FIRE practitioners mitigate this by maintaining some part-time income or keeping a larger cash buffer.

What savings rate do I need for each FIRE type?

Coast FIRE can be reached with a moderate 15 to 25% savings rate if you start in your 20s. Lean FIRE typically requires 50 to 70% savings rates for a 7 to 12 year timeline. Fat FIRE usually demands 40 to 60% savings rates over 12 to 20 years, or high income to sustain both comfortable spending and aggressive saving.