FIRE Calculator

The 4% rule is a retirement-planning heuristic, not a promise that a portfolio will last. It starts with a 4% withdrawal in year one and commonly assumes later withdrawals rise with inflation. This calculator uses the simpler FIRE-number formula: annual expenses divided by the withdrawal rate. At 4%, that equals annual expenses multiplied by 25. At 3.5%, it is annual expenses multiplied by about 28.6. Your actual withdrawal plan also depends on taxes, asset allocation, spending flexibility, and market returns.

Lean FIRE targets a bare-bones retirement budget, typically under $40,000 a year, which puts the FIRE number below $1,000,000 at a 4% rate. Fat FIRE targets $100,000 a year or more, requiring $2,500,000 or more. Most people land somewhere in between (sometimes called regular FIRE), with annual expenses in the $50,000 to $80,000 range and a corresponding portfolio of $1,250,000 to $2,000,000. These cutoffs are conventions, not fixed rules.

Coast FIRE is the point at which your current savings will compound to your full FIRE number by traditional retirement age, with no further contributions needed. This calculator shows that figure by growing your current balance at the expected return rate until age 65 (adjustable). If that projected value exceeds your FIRE number, you have already coasted: you only need to cover living expenses, not add more to investments.

Sequence-of-returns risk means a market downturn in the first few years of retirement can permanently deplete your portfolio, even if long-run average returns are fine. Selling shares at low prices locks in losses that compounding cannot fully recover. Common defenses include holding 1-2 years of expenses in cash, using a flexible withdrawal strategy that cuts spending in down years, or targeting a withdrawal rate below 4%.

For a 30-year retirement, the Trinity study found 4% had a 95%+ success rate. For early retirees with 40-50 year horizons, researchers such as Wade Pfau and Early Retirement Now suggest 3.3-3.5% to keep a similar safety margin. The right rate also depends on your spending flexibility: retirees willing to trim 10-15% of withdrawals in bad market years can tolerate a higher starting rate with lower risk of running out. This is an estimate, not personalized financial advice.