Lean FIRE vs Fat FIRE
Both are versions of financial independence, but they describe very different spending levels and therefore very different portfolio targets.
Lean FIRE
Lean FIRE usually means leaving full-time work with a relatively low spending target. The advantage is that the capital target is smaller. The downside is that the plan leaves less room for lifestyle inflation, surprises, or expensive goals later.
Fat FIRE
Fat FIRE means aiming for a much larger portfolio so retirement spending can be more flexible or more comfortable. It is harder to reach, but the plan may feel less fragile once you get there.
Why this matters
People often talk about FIRE as if it were one number. That is sloppy thinking. The target always depends on spending. If your spending assumption is unrealistic, your FIRE number is unrealistic too.
That is why it helps to move from labels to math: estimate annual spending, choose a withdrawal rate, and calculate the portfolio target. Then test whether your savings rate can realistically get you there.
Where Coast FIRE fits
Coast FIRE sits between accumulation and full independence. You have enough invested today that the balance may grow to your retirement target without major new contributions, assuming time and returns do the rest.