LeanFIRE vs FatFIRE Budget Calculator

Compare LeanFIRE, Standard FIRE, and FatFIRE budgets. Calculate your FIRE number and timeline to financial independence.

Minimalist lifestyle (15-25% savings rate)

Luxurious lifestyle (50-70% savings rate)

Percentage of income saved and invested

Lower for early retirement (3-3.5%), higher for late (4-5%)

FIRE Number = Annual Budget / SWR. LeanFIRE: $40k/0.04 = $1M. Standard: $60k/0.04 = $1.5M. FatFIRE: $100k/0.04 = $2.5M. Years = log(FIRE/PV) / log(1+r).
Current $50k savings, $80k income, 50% savings ($40k/year), 4% SWR: LeanFIRE ($1M) = 13 years, Standard ($1.5M) = 19 years, FatFIRE ($2.5M) = 28 years.

What is the difference between LeanFIRE, Standard FIRE, and FatFIRE?

LeanFIRE: $40k or less annual budget (minimalist, 15-25% savings rate). Standard FIRE: $60-80k budget (comfortable middle-class, 30-50% savings). FatFIRE: $100k+ budget (luxurious, 50-70% savings). All use the same 4% rule (or adjusted SWR), but target different lifestyle costs.

How is FIRE number calculated for each type?

FIRE Number = Annual Budget / SWR. LeanFIRE at 4% SWR: $40k / 0.04 = $1M. Standard FIRE: $60k / 0.04 = $1.5M. FatFIRE: $120k / 0.04 = $3M. Lower SWR (3%) increases FIRE number: Lean = $1.33M, Standard = $2M, Fat = $4M.

Which FIRE type is most achievable?

LeanFIRE is fastest (can be reached in 10-15 years with 50%+ savings). Standard FIRE takes 15-20 years. FatFIRE takes 20-30+ years due to high target numbers. However, many start with LeanFIRE, then grow to FatFIRE over time as income increases.

Can I combine FIRE types (hybrid approach)?

Yes! Many pursue "Coast FIRE" or "Barista FIRE" - reach LeanFIRE first, then work part-time/less stressful jobs while portfolio grows to FatFIRE levels. Others use "Bridge FIRE" - LeanFIRE until Social Security/pension kicks in, then upgrade lifestyle.