Coast FIRE Calculator

Coast FIRE is a financial independence milestone where you have accumulated enough in your investment portfolio that, even without making any more contributions, it will grow to your full FIRE number by your target retirement age. Once you reach Coast FIRE, you only need to earn enough to cover current living expenses, and your investments 'coast' to a full retirement portfolio on their own.

Traditional (full) FIRE requires having the complete portfolio needed to fund retirement indefinitely (typically 25x annual expenses). Coast FIRE requires a smaller portfolio today, relying on compound growth over time to reach the full FIRE number by retirement. The younger you are, the smaller the Coast FIRE number because time provides more compounding. Coast FIRE offers an earlier intermediate milestone to celebrate.

Once you reach Coast FIRE, you have the option to reduce work stress, switch to a less demanding or part-time job, take a career break, or work in a field you love regardless of pay. You no longer need to save aggressively for retirement; any earnings beyond current expenses are gravy. Many people find this milestone dramatically reduces financial anxiety even if they do not immediately change jobs.

A common assumption for long-term stock market returns is 7% (approximately the historical average real return of a broad US equity index after inflation). If you prefer a nominal (before inflation) return, the historical average is closer to 10%. For a conservative Coast FIRE calculation, use 5-6%. The Coast FIRE number is highly sensitive to the assumed return rate over many years, so consider calculating with multiple rates.

Yes. Coast FIRE is almost always reached before Full FIRE (assuming you are still years from retirement). The key insight is that Coast FIRE depends on time: the earlier in life you reach Coast FIRE, the smaller the portfolio required. For a 25-year-old with a 40-year runway at 7% growth, the Coast FIRE number is roughly 6.7% of the full FIRE target. The ratio increases as you age and have less time to compound.