Coast FIRE Calculator
Estimate when your current investments can grow to fund retirement without additional contributions.
Personal Information
Your age today. This is the starting point for the projection.
The age at which you plan to fully retire. Coast FIRE assumes no additional contributions after the Coast FIRE milestone.
How much you expect to spend per year in retirement, in today’s dollars.
Current Assets & Contributions
Total amount currently invested across retirement and taxable accounts. Includes 401(k), IRA, brokerage, and other long-term investments.
Amount you currently contribute to investments each month. Used to project growth until you reach Coast FIRE.
Investment Parameters
Expected average annual investment return before inflation.
Expected long-term annual inflation rate.
Percentage of your portfolio you plan to withdraw annually in retirement. Commonly 3–4%, based on historical market data (not guaranteed).
Coast FIRE Analysis
You’re 18 years from Coast FIRE.
Projection Chart
The best time to plant a tree was 20 years ago. The second best time is now.
About this calculator
Coast FIRE is the point at which your existing invested assets are large enough that, even without additional contributions, they can grow to fully fund your retirement by your chosen retirement age.
This Coast FIRE Calculator estimates when you reach that milestone and visualizes two potential paths: continuing to contribute versus letting your investments grow on their own.
Use this calculator to explore when saving becomes optional and work becomes a choice rather than a requirement.
What each input means
- Current age is your age today. This is the starting point for the projection.
- Retirement age is the age at which you plan to fully retire. Coast FIRE assumes no additional contributions after the Coast FIRE milestone.
- Annual spending in retirement is how much you expect to spend per year in retirement, in today’s dollars.
- Current invested assets is the total amount currently invested across retirement and taxable accounts. Includes 401(k), IRA, brokerage, and other long-term investments.
- Monthly contribution is the amount you currently contribute to investments each month. Used to project growth until you reach Coast FIRE.
- Investment growth rate is your expected average annual investment return before inflation.
- Inflation rate is the expected long-term annual inflation rate.
- Safe withdrawal rate is the percentage of your portfolio you plan to withdraw annually in retirement. Commonly 3–4%, based on historical market data (not guaranteed).
How does Coast FIRE work?
Coast FIRE is a variation of the FIRE (Financial Independence, Retire Early) framework. Instead of fully retiring early, Coast FIRE focuses on reaching a point where your retirement is already funded, as long as your investments continue to compound.
Once you reach Coast FIRE, you no longer need to save for retirement. Your existing investments can grow on their own over time, giving you the option to work less, change careers, or prioritize lifestyle flexibility.
The key idea is that time does the remaining work.
This calculator estimates the portfolio size needed today (your Coast FIRE number), whether your current assets can grow to support your retirement spending, and how long it may take to reach that point. It assumes steady investment returns and uses a safe withdrawal rate to estimate the total portfolio required at retirement.
Key levers that drive Coast FIRE outcomes
- Starting net worth – Higher current investments bring Coast FIRE closer.
- Time until retirement – More years allow compounding to do more of the work.
- Spending in retirement – Lower spending reduces the total portfolio required.
- Investment returns – Higher returns accelerate growth but increase uncertainty.
- Withdrawal rate – More conservative withdrawal rates require larger portfolios.
Key assumptions & limitations
- Constant returns – Investment returns are assumed to be constant.
- No market volatility modeled – Market volatility and sequence risk are not modeled.
- Steady inflation – Inflation is applied at a steady rate.
- Simplified taxes – Taxes are simplified and not dynamically calculated.
- Estimates only – Results are estimates, not financial advice.
This calculator is intended for high-level planning and comparison, not precise retirement forecasting.