Find out exactly when you can retire early, and what it takes to get there.
A FIRE number is the portfolio size that lets you cover a year of expenses through withdrawals alone, without ever running the principal down. Divide annual expenses by the withdrawal rate you are testing and that is the target.
A safe withdrawal rate is the share of your portfolio you take out each year, commonly cited around 4% based on how portfolios have historically held up over multi-decade periods. Divide 1 by that rate to get the multiple: at 4%, a FIRE number works out to 25 times annual expenses.
Coast FIRE is reached once your current balance, with no more contributions from you, will compound on its own to your full FIRE number by a target age. From that point, further saving becomes optional rather than required to hit the number by that age.
Not directly. The calculation divides annual expenses by a withdrawal rate, and both of those inputs are already in today's dollars, before prices have any chance to rise between now and the target date.
Your FIRE number (Financial Independence, Retire Early) is the investment portfolio size needed to sustain your annual expenses indefinitely through withdrawals alone, without depleting the principal over a normal lifetime. It's typically calculated as annual expenses divided by your assumed safe withdrawal rate. That portfolio might be a taxable brokerage account, a 401(k), an IRA, or a mix of accounts. The math here works the same regardless.
The safe withdrawal rate is the percentage of your portfolio you withdraw each year, historically often set around 4% based on studies of how portfolios have held up across decades of market history. That means a FIRE number is roughly 25x your annual expenses (since 1 ÷ 4% = 25). A lower withdrawal rate produces a larger FIRE number and a longer time to reach it; a higher withdrawal rate produces a smaller FIRE number and a shorter time to reach it.
This assumes the classic 4%-rule premise: your portfolio isn't meant to run out. Withdrawing a sustainable rate like this each year has historically allowed the remaining balance to keep growing, covering your expenses indefinitely rather than depleting to zero. This is different from the Withdrawal Tool tool, which shows exactly when a fixed corpus would run out under different withdrawal rates. Use that tool if you want to model a portfolio that does deplete.
Coast FIRE is a related but different milestone: the point where your current investments, left alone with no further contributions, will grow through compounding alone to reach your full FIRE number by a target age. Once you hit Coast FIRE, you could theoretically stop saving for retirement entirely and still get there, though most people keep contributing to retire sooner or with more of a cushion.