Coast FIRE Calculator

What Is Coast FIRE? A Path to Financial Flexibility

Coast FIRE (Financial Independence, Retire Early) is a major milestone on the path to financial independence. It means you have saved and invested enough money that, without contributing another dollar, your portfolio will grow to support a traditional retirement by age 65. Once you hit your Coast FIRE number, your investment's compound growth does the rest of the heavy lifting.

This doesn't mean you retire immediately. Instead, it means you are no longer required to save for retirement. You only need to earn enough to cover your current living expenses, giving you immense career and life flexibility. You can switch to a less demanding job, pursue a passion project, or work part-time, all with the peace of mind that your retirement is already secured. Our Coast FIRE calculator is designed to find that exact number for you.

How to Use Our Coast FIRE Calculator

This comprehensive FIRE calculator is designed to provide a clear, actionable picture of your journey to financial independence. It requires a few key inputs about your financial life to generate its projections.

Understanding the Inputs

• Current Age & Retirement Age: Defines the timeline for your investments to grow. The longer the timeline, the more powerful compound interest becomes.
• Current Investment Balance: The starting point for your portfolio.
• Annual Expenses in Retirement: Your estimated yearly spending in today's dollars. This is used to calculate your total retirement nest egg.
• Monthly Savings: The amount you are currently contributing to your investments. This helps the calculator estimate how long it will take you to reach your Coast FIRE number.
• Advanced Settings (Return, Inflation, Withdrawal Rate):These three assumptions are critical for an accurate forecast. We use a 7% expected return, 3% inflation, and 4% withdrawal rate as common, sensible defaults.

Interpreting Your Results

Once you input your data, the calculator provides several key metrics:

• Your Coast FIRE Number: This is the magic number. It's the amount you need in your investment accounts todayto be able to coast to a full retirement.
• Current Gap: The difference between your current balance and your Coast FIRE number.
• Future Value of Investments: A projection of what your current balance will grow to by retirement age, assuming you stop saving completely.
• Time to Coast FIRE: An estimate of how many years and months it will take to reach your goal at your current savings rate.

The Formula: How We Calculate Your Coast FIRE Number

1. Step 1: Project Future Annual Expenses. We first calculate what your desired annual expenses will be in the future, adjusted for inflation.
   Future Expenses = Annual Expenses * (1 + Inflation Rate) ^ Years to Retirement
2. Step 2: Calculate Target Retirement Amount. Next, we determine your total nest egg needed at retirement using the 4% Safe Withdrawal Rate (SWR) rule.
   Target Amount = Future Expenses / (Withdrawal Rate / 100)
3. Step 3: Calculate Your Coast FIRE Number. Finally, we calculate the present value of that future target amount. This tells us how much money you need today that will grow to the target amount, based on your expected investment return.
   Coast FIRE Number = Target Amount / (1 + Expected Return) ^ Years to Retirement

This inflation-first approach ensures a much more realistic and accurate goal compared to simpler calculators.

Coast FIRE vs. Traditional FIRE vs. Barista FIRE

The FIRE movement has many flavors. Here’s how Coast FIRE compares to other popular approaches:

• Traditional FIRE: You have saved 25x your annual expenses and can retire completely, living off your investments indefinitely.
• Coast FIRE: You have saved enough that your portfolio will grow to your FIRE number on its own. You still work to cover current expenses but no longer need to save for retirement.
• Barista FIRE: A form of Coast FIRE where someone quits their high-stress primary job and takes a part-time job (like a barista) to cover living expenses, often for the health insurance benefits, while their investments continue to grow.

Frequently Asked Questions (FAQ)

What happens after I reach my Coast FIRE number?

Reaching Coast FIRE gives you options. You can:

1. Stop saving for retirement entirely and use that extra cash flow to enhance your lifestyle, travel, or reduce your work hours.
2. Continue saving to reach Traditional FIRE much earlier than your target retirement age.
3. Take a lower-paying "passion" job without worrying about its retirement benefits.

Is the 4% Safe Withdrawal Rate (SWR) still reliable?

The 4% rule, based on the Trinity Study, is a widely used benchmark in retirement planning. It suggests you can withdraw 4% of your initial portfolio value each year (adjusted for inflation) with a very low probability of running out of money over 30 years. While it's a solid starting point, some financial planners now suggest a more conservative rate of 3.5% to 3.8% to account for modern market volatility. Our calculator allows you to adjust this rate in the advanced settings.

How do I account for taxes in my calculation?

This calculator's projections are pre-tax. When estimating your "Annual Expenses in Retirement," you should consider your total spending needs, including what you'll owe in taxes on withdrawals from accounts like a traditional 401(k) or IRA. Roth IRA withdrawals are tax-free, which can significantly impact your retirement plan.

What's a realistic "Expected Annual Return"?

Historically, the stock market (like the S&P 500) has returned an average of about 10% annually before inflation. A common and reasonably conservative estimate for long-term planning is 7% after inflation, which is the default we use in this calculator. You can adjust this number based on your own risk tolerance and investment strategy.

Example with inflation:
Current expenses: $60,000, 3% inflation, 7% returns, 30 years to retirement:

• Future expenses: $60,000 × (1.03)^30 = $145,537
• Target amount: $145,537 ÷ 0.04 = $3,638,425
• Coast FIRE: $3,638,425 ÷ (1.07)^30 = $478,006

This means you need $478,006 today to maintain $60,000 of today's purchasing power in retirement.

Strategies to Reach Your Coast FIRE Number Faster

Once you know your Coast FIRE target, these strategies can help you reach it more quickly:

• Maximize Early Career Earnings: Invest in skills and career advancement
• High Savings Rate: Save 50%+ of income in your 20s and early 30s
• Tax-Advantaged Accounts: Maximize 401(k), IRA, and HSA contributions
• Low-Cost Index Funds: Minimize fees to maximize returns
• Side Income: Accelerate savings with additional income streams
• Geographic Arbitrage: Reduce expenses by living in lower-cost areas

Frequently Asked Questions (FAQ)

What happens if I reach Coast FIRE but want to retire earlier?

Reaching Coast FIRE gives you options. You can continue saving to achieve full FIRE for early retirement, or you can reduce your savings rate and enjoy more lifestyle flexibility while still ensuring traditional retirement security. Many people use Coast FIRE as a stepping stone to full FIRE.

Can I still contribute to investments after reaching Coast FIRE?

Absolutely! Coast FIRE represents the minimum needed to reach FI. Additional contributions will either allow earlier retirement or a more comfortable retirement lifestyle. Many Coast FIRE achievers continue investing at a reduced rate for extra security and flexibility.

How accurate is the Coast FIRE calculation?

Our coast fire calculator uses established financial formulas, but results depend on your assumptions about investment returns, inflation, and future expenses. Consider using conservative estimates and planning for multiple scenarios. The calculation becomes more accurate as you get closer to retirement and have better data about your spending needs.

What if my expenses change in retirement?

Retirement expenses often differ from working years—you might spend less on commuting and work clothes but more on healthcare and leisure. Our calculator lets you adjust your annual expense target. Many financial planners recommend using 70-90% of pre-retirement income, but your actual needs may vary significantly based on your lifestyle and goals.