FIRE Number Calculator

The 4% rule is a rule of thumb used to determine how much you can withdraw from your retirement portfolio each year without running out of money. It is based on the 1998 "Trinity Study," which looked at historical market data and concluded that a portfolio of 50% stocks and 50% bonds could sustain a 4% inflation-adjusted withdrawal rate over a 30-year period.

Many modern financial analysts believe 4% may be slightly too aggressive for early retirees (who need the portfolio to last 40-50 years, not just 30). The 2026 Morningstar consensus research suggests a safe withdrawal rate (SWR) of closer to 3.9% for a standard balanced portfolio. If you want extreme safety, some FIRE practitioners use a 3.25% or 3.5% withdrawal rate.

Coast FIRE means you have already saved enough money that, even if you never invest another penny, your portfolio will grow to your target FIRE number by the time you reach traditional retirement age (e.g., 65). Once you reach Coast FIRE, you only need to earn enough to cover your current living expenses.