Lean FIRE vs Fat FIRE
The three versions of the same finish line differ only in the spending they fund - but because the pot is a multiple of spending, small lifestyle differences become enormous portfolio differences. The comparison chart below shows all three on your numbers.
Open an investment account
We explain exactly what to compare before you open anything - costs, protection and the traps.
The multiplier effect of spending
At a 4% withdrawal rate, every extra 1,000 of annual spending adds 25,000 to the pot required. A 20,000 lifestyle difference is a 500,000 portfolio difference.
Lean FIRE here is modelled at 70% of your stated spending and Fat FIRE at double it. Those are conventions rather than definitions - adjust your spending figure to see your own version.
Which one is actually right
Lean FIRE arrives years earlier but leaves little margin for a bad market, a health problem or a change of mind. Fat FIRE is resilient but expensive in working years.
Most people land somewhere in between, then keep some earning capacity for the first few years. That combination handles sequence risk better than either extreme.
Frequently asked questions
What counts as Lean FIRE?
Commonly a plan funding a deliberately modest lifestyle, often described as under 25,000-40,000 a year for a household depending on the country.
What counts as Fat FIRE?
A plan funding comfortably above median spending without compromise - frequently 100,000 a year or more.
Is Lean FIRE risky?
It has less room to absorb surprises. A lower withdrawal rate or some continued income reduces that risk considerably.
Can I start lean and upgrade later?
Yes, and many do. Continuing to invest after reaching Lean FIRE converts time into a higher sustainable income.
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