What is Lean FIRE?
Lean FIRE targets a minimal retirement lifestyle, typically defined as annual spending below $40,000 (or below $25,000 for very lean planners). The appeal is mathematical: a lower spending target requires a much smaller portfolio. At $30,000 per year, your FIRE number is $750,000. At $25,000, it is $625,000.
Lean FIRE planners often live in lower cost-of-living areas, own their home outright, and have minimal discretionary spending. Many find that a lean lifestyle is not a sacrifice — simplified living can reduce stress, increase free time, and align better with personal values.
What is Fat FIRE?
Fat FIRE targets $100,000 or more per year in retirement spending — full lifestyle flexibility including travel, dining, and comfortable housing. At $120,000 per year, the FIRE number is $3,000,000. Fat FIRE requires either a very high income, a very long accumulation period, or both. It is the slower but more comfortable path.
Fat FIRE is often the goal for households with children, high current lifestyle costs they do not want to reduce, or professions where income is high enough that aggressive saving is feasible without lifestyle sacrifice.
The spectrum in between: Regular FIRE
Most FIRE planners target somewhere in the middle — annual spending of $50,000–$80,000, requiring a portfolio of $1,250,000–$2,000,000. This range is often called "regular FIRE" and allows for a comfortable middle-class lifestyle without requiring either extreme frugality or an exceptionally high income.
How to choose your target
The honest question is: what does your ideal retirement day actually look like? Start with a detailed spending plan for retirement — not your current expenses, but your desired ones. Include healthcare, housing, travel, food, and discretionary spending. Multiply by 25 and that is your number. Then ask whether you can realistically reach that number in a timeline that motivates you.
A Lean FIRE target that you can hit in 10 years often beats a Fat FIRE target that takes 25 years, depending on how much you want your current life to change. Many people start with Lean FIRE as a floor and plan to grow into Fat FIRE over time through part-time work or investment growth beyond their target.
Geographic arbitrage and the spending target
One powerful lever: retirement location. Retiring to a low cost-of-living city, region, or country can transform a Fat FIRE lifestyle budget into a Lean FIRE portfolio requirement. A $100,000 annual budget in San Francisco might only require $45,000 in Mexico City or Chiang Mai — reducing the required portfolio from $2,500,000 to $1,125,000.