FIRE — Financial Independence, Retire Early — sounds aspirational. The math behind it is high-school arithmetic.
Calculators do the heavy lifting, but knowing what is going on underneath is what saves you money — or stress — later. FIRE — Financial Independence, Retire Early — sounds aspirational. The math behind it is high-school arithmetic.
Annual spending × 25 = your FIRE number. Based on the 4% safe-withdrawal rule from the Trinity Study.
Save 25% of income → ~32 years to FIRE. Save 50% → ~17 years. Save 70% → ~9 years. Income matters less than rate.
Lean = $40k/yr ($1M number). Fat = $100k/yr ($2.5M number). Coast FIRE = enough invested young that compounding alone finishes the job.
Is 4% still safe? Most updated studies say 3.3–3.7% is safer for early retirees with 50+ year horizons.
What about healthcare in the US? Add $12–24k/yr for ACA plans before age 65; this is often the unmodelled cost that breaks plans.
Bookmark the calculator linked above — you will need it more often than you think.