🏖️ CoastFIRE Calculator
Calculate when you can stop saving and let your investments coast to retirement
Calculate Your CoastFIRE Number
Your CoastFIRE Results
What is CoastFIRE?
CoastFIRE (Coast Financial Independence Retire Early) is a milestone on the path to financial independence where you've saved enough that your investments will grow to support your retirement without any additional contributions. Once you reach your CoastFIRE number, you can stop saving for retirement and simply "coast" while your money grows through compound interest.
Unlike traditional FIRE where you need enough money to retire immediately, CoastFIRE gives you the freedom to pursue lower-paying but more fulfilling work, reduce your hours, or take career risks without worrying about retirement savings. Your nest egg is already secured—it just needs time to grow.
How CoastFIRE Works
The concept is elegantly simple: if you save aggressively early in your career, compound interest does the heavy lifting for the remaining years until retirement. The earlier you reach your CoastFIRE number, the more financial freedom you gain in your working years.
The calculation involves three key components:
- Your FIRE Number: The total amount needed to retire (Annual Expenses Ă· Withdrawal Rate)
- Years Until Retirement: How long your money has to grow
- Expected Return Rate: The annual growth rate of your investments
The CoastFIRE Formula
The CoastFIRE number is calculated by determining how much you need today so that it grows to your FIRE number by retirement age, using the present value formula:
CoastFIRE Number = FIRE Number / (1 + Return Rate)^Years
Example Calculation:
Scenario: Sarah is 30 years old, wants to retire at 65, needs $40,000 per year in retirement, expects 7% annual returns, and uses a 4% withdrawal rate.
FIRE Number: $40,000 Ă· 0.04 = $1,000,000
Years to Retirement: 65 – 30 = 35 years
CoastFIRE Number: $1,000,000 / (1.07)^35 = $93,663
Result: If Sarah saves $93,663 by age 30 and never contributes another dollar, it will grow to $1,000,000 by age 65, allowing her to withdraw $40,000 annually in retirement.
Benefits of CoastFIRE
- Career Flexibility: Take lower-paying jobs that align with your passions without retirement anxiety
- Reduced Stress: No pressure to maximize income or maintain aggressive savings rates
- Work-Life Balance: Option to work part-time or take sabbaticals
- Geographic Freedom: Move to lower cost-of-living areas without career concerns
- Entrepreneurial Opportunities: Start a business without risking retirement security
- Early Achievement: Reach this milestone years or decades before full FIRE
Strategies to Reach CoastFIRE Faster
- Start Early: The power of compound interest is maximized with time—every year earlier dramatically reduces the amount you need to save
- Maximize Savings Rate: In your 20s and early 30s, aim for a 50%+ savings rate to accelerate your timeline
- Optimize Investment Returns: Use low-cost index funds and maintain an appropriate asset allocation for growth
- Increase Income: Negotiate raises, switch jobs strategically, or develop side income streams
- Reduce Retirement Expenses: The lower your target annual expenses, the smaller your CoastFIRE number
- Take Advantage of Tax-Advantaged Accounts: Maximize 401(k) and IRA contributions for tax-free growth
Important Considerations
Healthcare Costs: Remember to include healthcare expenses in your retirement budget, especially if you plan to retire before Medicare eligibility at 65.
Inflation: Your retirement expenses should account for inflation. Consider using inflation-adjusted numbers or adding a buffer to your target amount.
Market Volatility: Investment returns fluctuate. The 7% average return includes down years, so having a cushion above your minimum CoastFIRE number provides security.
Sequence of Returns Risk: Market performance in the years immediately before retirement significantly impacts your success. Monitor your portfolio as you approach retirement age.
CoastFIRE vs. Other FIRE Variations
Traditional FIRE: Requires 25-30x annual expenses saved to retire immediately. CoastFIRE requires significantly less upfront.
BaristaFIRE: Similar to CoastFIRE but assumes part-time work will also cover living expenses, not just that you'll stop saving. CoastFIRE assumes your current earnings cover expenses while investments grow.
LeanFIRE: Retiring on a minimal budget (typically under $40,000/year). CoastFIRE is methodology-focused rather than expense-level focused.
FatFIRE: Retiring with a luxurious lifestyle (typically $100,000+/year). You can achieve CoastFIRE for any expense level, including FatFIRE.
Real-World Example Scenarios
Aggressive Early Saver:
Profile: Alex, age 25, software engineer, current savings: $75,000
Goals: Retire at 60 with $50,000/year expenses
FIRE Number: $1,250,000 (using 4% rule)
CoastFIRE Number: $178,431
Outcome: Alex is already 42% of the way to CoastFIRE at 25! With another $103,431 saved, Alex can stop contributing and the money will grow to $1,250,000 in 35 years at 7% returns.
Mid-Career Professional:
Profile: Jamie, age 40, teacher, current savings: $200,000
Goals: Retire at 65 with $35,000/year expenses
FIRE Number: $875,000 (using 4% rule)
CoastFIRE Number: $181,219
Outcome: Jamie has already exceeded CoastFIRE! The current $200,000 will grow to $1,085,000 in 25 years, providing more than needed for retirement. Jamie can now focus on work-life balance or pursue passion projects.
Tracking Your CoastFIRE Progress
Monitor your journey with these metrics:
- CoastFIRE Percentage: (Current Savings Ă· CoastFIRE Number) Ă— 100
- Projected Retirement Value: Current Savings Ă— (1 + Return)^Years
- Monthly Contribution Needed: Calculate if you're not yet at CoastFIRE
- Annual Reviews: Reassess assumptions about returns, expenses, and retirement age
What to Do After Reaching CoastFIRE
Once you hit your CoastFIRE number, you have several options:
- Continue Saving: Reach full FIRE faster or build a larger cushion
- Reduce Work Hours: Move to part-time or freelance work
- Career Change: Pursue meaningful work regardless of salary
- Geographic Arbitrage: Move to a dream location even if job opportunities are limited
- Start a Business: Take entrepreneurial risks with a safety net
- Invest in Experiences: Travel, education, or hobbies while still working
Common Mistakes to Avoid
Underestimating Expenses: Be realistic about retirement costs including healthcare, housing maintenance, and lifestyle inflation.
Overestimating Returns: Using 10%+ expected returns is overly optimistic. Historical stock market average is 7% after inflation.
Ignoring Taxes: Consider whether savings are in traditional or Roth accounts and plan for tax implications.
Stopping Too Early: Market downturns near retirement can derail plans. Build in a buffer or monitor closely as retirement approaches.
Lifestyle Creep: After reaching CoastFIRE, avoid increasing expenses so much that your retirement number becomes inadequate.
Conclusion
CoastFIRE represents a balanced approach to financial independence that doesn't require extreme frugality for decades. By saving aggressively early in your career, you can achieve the freedom to make life decisions based on fulfillment rather than financial necessity, all while maintaining a secure retirement trajectory.
Use this calculator to determine your CoastFIRE number and start planning your path to financial freedom. Remember that these calculations are projections—regularly review and adjust based on life changes, market performance, and evolving goals. The journey to CoastFIRE is as valuable as the destination, teaching discipline, intentionality, and the power of compound interest.