Coast FIRE Calculator
Calculate when you can stop saving and let compound growth carry your portfolio to your FIRE number.
The percentage of your portfolio you plan to withdraw annually in retirement.
Your Coast FIRE Number
$197,051
At your current savings rate, you'll reach this in 6.9 years (age 36.9).
FIRE Number
$1,500,000
At 4.0% withdrawal rate
Coast Number
$197,051
Today's target
Current Progress
50.7%
Toward coast number
Years to Coast
6.9
Age 36.9
How to Use This Calculator
Enter your current age, target retirement age, expected annual expenses in retirement, and your current portfolio value. The calculator computes your full FIRE number (the portfolio that sustains your spending indefinitely) and your Coast FIRE number (the amount you need today so that compound growth alone reaches your FIRE number by retirement). Adjust the return rate and withdrawal rate to model different scenarios.
What Is Coast FIRE?
Coast FIRE is a milestone on the path to financial independence where your invested assets are large enough that compound growth alone will grow them to your full FIRE number by your target retirement age. No additional savings are required — your money “coasts” to the finish line on its own.
This is a powerful concept because it decouples your savings rate from your retirement timeline. Once you pass the coast threshold, you can redirect your income toward lower-stress work, travel, education, or passion projects — as long as you cover your current living expenses.
Coast FIRE is especially appealing to younger savers who benefit from decades of compounding. A 25-year-old with a 7% expected return and a 35-year horizon needs a coast number that is roughly 1/10th of their full FIRE number — a much more approachable target.
How Coast FIRE Works
The math behind Coast FIRE is present value discounting. Your full FIRE number is a future target — the portfolio size that sustains your retirement spending. The coast number is that future target discounted back to today at your expected investment return rate.
For example, if your FIRE number is $1,500,000 and you expect a 7% annual return over 30 years, your coast number is approximately $197,000. If your portfolio already exceeds that amount, you are mathematically on track to reach $1.5M by retirement even if you never save another dollar.
The chart above shows two paths: your portfolio growing with continued contributions (the solid area) and your portfolio growing without contributions (the dashed line). The declining amber line is your coast target — the amount needed at each age to reach your FIRE number by retirement. When your portfolio crosses above the coast target line, you've reached Coast FIRE.
Frequently Asked Questions
What is Coast FIRE?
Coast FIRE is the point where your invested portfolio is large enough that, even without any additional contributions, compound growth alone will grow it 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.
How is the Coast FIRE number calculated?
The Coast FIRE number is your full FIRE number (annual expenses divided by your safe withdrawal rate) discounted back to today using your expected investment return rate and the number of years until retirement. It represents the present value of your future FIRE number.
What is a safe withdrawal rate?
The safe withdrawal rate (SWR) is the percentage of your portfolio you can withdraw annually in retirement with a high probability of not running out of money over a 30-year period. The most commonly cited rate is 4%, based on the Trinity Study, though many FIRE practitioners use 3.5% or lower for longer retirement horizons.
Does this calculator account for inflation?
Yes. You can set an expected inflation rate, which is factored into the real return calculation. The default 7% nominal return with 3% inflation yields approximately a 3.9% real return rate. All dollar figures are shown in nominal terms unless otherwise noted.
What happens after I reach Coast FIRE?
After reaching Coast FIRE, you can shift to lower-paying but more fulfilling work, reduce hours, or pursue other interests — as long as you earn enough to cover your current living expenses. Your existing portfolio grows on autopilot to your full FIRE number.
Related Calculators
Methodology & Assumptions
The Coast FIRE number is computed as the present value of your FIRE number discounted at your expected return rate. The projection series models year-by-year portfolio growth with and without contributions. All calculations are performed client-side — no data is sent to any server.
This tool provides estimates for educational purposes. It is not financial advice. Consult a fee-only financial planner before making major retirement decisions.