FIRE Calculator

FIRE stands for Financial Independence, Retire Early. The core idea: a high savings rate builds a portfolio large enough to live off its returns — freeing you from mandatory employment decades before the traditional retirement age.

Your FIRE number is calculated by dividing your annual expenses by your safe withdrawal rate. At a 4% SWR, someone spending $50,000/year needs $1,250,000 to reach financial independence. At 3.5%, that number rises to about $1,428,571.

Why Savings Rate Matters More Than Income

The single most powerful lever in the FIRE equation is your savings rate — the percentage of income you invest. A higher savings rate works in two directions simultaneously: it increases the money flowing into investments and it decreases the spending level you need to sustain in retirement (lowering your FIRE number). Someone saving 50% of their income can typically reach FI in about 17 years, regardless of income level. At 70%, it drops to roughly 8.5 years.

The 4% Rule and Safe Withdrawal Rates

The 4% rule comes from the Trinity Study, which found that a diversified portfolio (stocks and bonds) historically survived 30-year withdrawal periods at a 4% initial withdrawal rate, adjusted for inflation, with a high success rate. More conservative FIRE practitioners use 3% or 3.5% to account for longer retirement horizons, lower expected returns, or sequence-of-returns risk.

Types of FIRE

Lean FIRE: Achieving FI on a below-average spending level (typically under $40,000/year for a household). Requires significant lifestyle optimization but achievable on moderate incomes.

Fat FIRE: Reaching FI with a higher spending level ($100,000+/year), preserving a comfortable lifestyle without frugality constraints. Requires either very high income or many years of saving.

Barista FIRE / Coast FIRE: Partial financial independence where you have enough saved that compound growth alone will fund retirement — you only need to cover current expenses with part-time or lower-stress work. See our Coast FIRE Calculator.

Common FIRE Mistakes

Ignoring inflation: A FIRE number is either stated in real (inflation-adjusted) terms, or its withdrawal plan adjusts annually for inflation. This calculator uses real returns (nominal return minus inflation) to keep projections honest.

Underestimating healthcare costs: Medicare eligibility starts at 65, so earlier retirees self-insure. ACA marketplace plans for a family can easily cost $15,000–$30,000/year, which significantly increases your FIRE number.

Ignoring taxes: Withdrawals from traditional 401(k) and IRA accounts are taxed as ordinary income, so a FIRE number built on pre-tax balances overstates what’s spendable. A Roth conversion ladder converts those balances over a series of years, each conversion taxed in the year it happens.