What Is Coast FIRE?
Coast FIRE (also called Coast FI) is a milestone on the path to Financial Independence, Retire Early where you have saved and invested enough money that, even without any additional contributions, your portfolio will grow to your full retirement number by your target retirement age through compound growth alone. Once you reach Coast FIRE, you only need to earn enough to cover your current living expenses — you no longer need to save for retirement.
For example, if you need $2,500,000 at age 60 and you expect a 7% annual return, you would need approximately $637,000 at age 40. Once your portfolio reaches $637,000, compounding does the rest. You can switch to a lower-stress job, work part-time, or pursue passion projects without worrying about retirement savings.
How to Use This Coast FIRE Calculator
- 1
Enter Your Current Situation
Input your current age, current net worth (investable assets), and expected annual return on investments. A 7% return is the historical average for a diversified stock portfolio after inflation.
- 2
Set Your Retirement Expectations
Enter your target retirement age, how much you plan to spend annually in retirement, and your safe withdrawal rate (typically 4% based on the Trinity Study). The calculator uses these to determine your full retirement number.
- 3
Configure Contributions
Set your regular contribution amount and frequency (monthly, quarterly, or annually). Optionally add a contribution growth rate to model salary increases over time.
- 4
Get Your Coast FIRE Results
Click Get Result to see your Coast FIRE number, the age you will reach it, and your full retirement projection. The interactive chart shows your net worth growth alongside the Coast FIRE goal line and full retirement target.
How Is the Coast FIRE Number Calculated?
The Coast FIRE number is derived from the future value formula, solved in reverse. Your full retirement goal is your annual spending divided by your withdrawal rate. Then the Coast FIRE number is the present value of that goal:
Full Retirement Goal = Annual Spending / Withdrawal Rate
Coast FIRE Number = Full Retirement Goal / (1 + r)^n
Where r = expected annual return and n = years until retirement
Example: $2,500,000 / (1.07)^20 = $646,083 Coast FIRE number
Once your portfolio reaches this number, you have achieved Coast FIRE. Compounding will grow your investments to your retirement goal without any further contributions. The higher your expected return or the more years until retirement, the lower your Coast FIRE number.
Coast FIRE vs Other FIRE Variations
Coast FIRE
You have enough invested that compounding alone will reach your retirement goal. You only need to cover current expenses — no more saving required. Ideal for those who want to reduce work stress early.
Barista FIRE
Semi-retirement where part-time work covers living expenses and health insurance while your portfolio grows. Similar to Coast FIRE but explicitly involves part-time employment.
Lean FIRE
Full financial independence on a minimal budget, typically under $40,000 per year. Requires a smaller portfolio but demands a frugal lifestyle in retirement.
Fat FIRE
Full financial independence with a comfortable or luxurious lifestyle, typically $100,000+ per year. Requires a much larger portfolio but allows for travel, hobbies, and premium living.
Benefits of Reaching Coast FIRE
Reduced Stress
Knowing your retirement is secured lets you choose work based on fulfillment rather than salary. Take a pay cut for a dream job without financial anxiety.
Career Flexibility
Switch to part-time work, freelancing, or a passion project. Your retirement savings grow on autopilot while you pursue what matters most.
Achievable Earlier
Coast FIRE is typically reached years or decades before full FIRE. It is the most accessible FIRE milestone for most people, providing benefits much sooner.