Coast FIRE Calculator
Have you saved enough already? See if compound interest can bridge the gap to retirement.
How This Tool Works
Coast FIRE is the financial inflection point where you've saved enough that you no longer need to add another dollar to your retirement accounts—compound interest will take you the rest of the way.
- The Math: We take your retirement target (based on the Rule of 25) and "reverse-engineer" how much you need today based on the time left and your growth rate.
- Logic: If you need $1M at 65 and are 35 today, we calculate what amount grows to $1M in 30 years at your chosen rate of return.
- The "Coast" Benefit: Once reached, you only need to earn enough to cover your current lifestyle, allowing for career changes or part-time work.
How to Use (Steps)
- Current & Retirement Age: Defines your "Time Horizon" for the money to grow.
- Annual Spending: The amount you plan to spend per year in retirement.
- Invested Assets: What you have in the market right now.
- Growth Rate: 7% is the historical real return of the S&P 500.
Example Calculation
Scenario: 30 years old, retiring at 60.
• Future Need: $1,250,000 ($50k spend).
• Time Horizon: 30 Years.
• Growth Rate: 7%.
• Coast FIRE Number: $164,203.
• Verdict: If you have $165k today, you are "Coasting" and can stop retirement saving.
Why This Tool Is Accurate
This tool uses the time-value of money formula to give you a definitive "Stop Saving" date. It empowers you to scale back high-stress work years or decades earlier than traditional retirement would suggest.
Limitations & Disclaimer
The "Growth Rate" is extremely sensitive. A 1% difference in returns over 30 years can result in a massive gap in your final balance. Always use conservative growth estimates (5-6%) to ensure a margin of safety.
Frequently Asked Questions
Full FIRE means you have reached your target and can stop working entirely. Coast FIRE means you have saved enough to stop contributing, but you still need to work to cover your daily living expenses until you reach retirement age.
It depends on your goals. Hitting Coast FIRE gives you the option to stop. Many people continue saving to reach "Full FIRE" even faster, while others use the extra cash flow to travel more or work a lower-paying "dream job."
This calculator focuses solely on your private investments. If you expect Social Security income, you can subtract that expected amount from your "Annual Spend" to see a lower, more attainable Coast FIRE number.