What is Coast FIRE?

Understanding Coast FIRE

The traditional Financial Independence, Retire Early (FIRE) path often involves a grueling decade or more of saving 50% to 70% of your income to reach full financial independence as quickly as possible. While effective, this "sprint" can lead to extreme burnout and requires sacrificing many present-day luxuries.

Coast FIRE offers a different, arguably more sustainable approach. Coast FIRE is achieved when you have saved enough money in your investment accounts at an early age that—assuming a conservative historical rate of return—that money will grow to hit your full FI number by traditional retirement age (usually 65), without you ever needing to contribute another dime.

Once you hit your Coast FI number, you can take your foot off the gas. You no longer need to save for retirement. You simply need to earn enough active income to cover your current, day-to-day living expenses. This allows you to downshift into a lower-paying but more fulfilling career, start a risky business, or transition to part-time work decades before traditional retirement.

How to Calculate Your Coast FI Number

Calculating your Coast FI number requires working backward from your ultimate retirement goal. You need three pieces of information:

1. Your Target FI Number: How much you need to fully retire (e.g., $1,000,000).
2. Years to Grow: The number of years between your current age and your traditional retirement age (e.g., age 65 minus age 30 = 35 years).
3. Expected Rate of Return: The inflation-adjusted (real) return you expect from your investments (often estimated at 5% to 7%).

The formula uses the present value equation:

A Real-World Example

Let's say Sarah is 30 years old. She determines she needs $1.2 million to fully retire at age 65. She expects a conservative 5% real return after inflation. She has 35 years for her money to grow.

• Target FI: $1,200,000
• Return: 5% (0.05)
• Years: 35
• Calculation: $1,200,000 / (1 + 0.05) ^ 35

Sarah's Coast FI number is approximately $217,549.

If Sarah has $217,549 invested at age 30, she has achieved Coast FIRE. She can immediately stop contributing to her 401(k) and IRAs. As long as she doesn't touch that $217k and it grows at 5% annually, she will have $1.2 million when she turns 65.

The Benefits of Coast FIRE

Why choose Coast FIRE over the traditional FIRE sprint?

• Alleviates Burnout: Knowing your retirement is mathematically secured significantly reduces the stress of your primary career.
• Enables Career Transitions: You can take a massive pay cut to work a job you actually love, knowing you only need to cover your rent, groceries, and basic bills.
• Encourages Present-Day Spending: Because you no longer need a 50% savings rate, you can spend your current income on travel, experiences, or a nicer home without feeling guilty about delaying your retirement.
• Protects Against Sequence of Returns Risk: Because you aren't drawing down your portfolio early, you aren't exposed to the risk of an early market crash devastating your principal. (Learn more about Sequence of Returns Risk).

Coast FIRE vs. Barista FIRE vs. Lean FIRE

The FIRE community loves its sub-categories. How does Coast FIRE compare to other strategies?

Is Coast FIRE Right for You?

Coast FIRE is particularly effective for people in their 20s and early 30s. Because compound interest is heavily dependent on time, the earlier you front-load your investments, the lower your Coast FI number will be.

However, it does require a leap of faith in market returns and a willingness to continue working (albeit in a potentially more enjoyable capacity) for decades. If your ultimate goal is to never punch a clock again as soon as possible, traditional full FIRE remains the better path.