Coast FIRE is the most accessible version of financial independence — and possibly the most life-changing. Unlike traditional FIRE which requires decades of aggressive saving, Coast FIRE means you've saved enough that compound growth alone will carry you to a comfortable traditional retirement, even if you never invest another dollar.
What Is Coast FIRE?
Coast FIRE (also called "Coast FI") is the point where your existing investments, left untouched, will grow to support a traditional retirement by age 60-65 through compound interest alone. Once you reach this number, you only need to earn enough to cover your current living expenses — no more saving required.
This means you can "coast" — take a lower-paying but more fulfilling job, work part-time, freelance, or pursue passion projects without worrying about retirement savings.
The Coast FIRE Formula
The formula is straightforward:
Coast FIRE Number = FI Number ÷ (1 + growth rate)^years until retirement
Where:
- FI Number = Annual expenses × 25 (using the 4% rule)
- Growth rate = Expected real return (typically 7% for stocks)
- Years until retirement = Target retirement age minus current age
Coast FIRE Numbers by Age
Assuming $40,000/year in retirement expenses ($1,000,000 FI number) and 7% real returns:
- Age 25: Coast FIRE number = $131,000 (35 years of growth)
- Age 30: Coast FIRE number = $184,000 (30 years of growth)
- Age 35: Coast FIRE number = $258,000 (25 years of growth)
- Age 40: Coast FIRE number = $362,000 (20 years of growth)
- Age 45: Coast FIRE number = $508,000 (15 years of growth)
Notice how powerful starting early is. A 25-year-old only needs $131,000 to "coast" to a million-dollar retirement portfolio.
Coast FIRE vs. Traditional FIRE vs. Lean FIRE
Understanding where Coast FIRE fits in the FIRE spectrum:
- Lean FIRE: Full FI with minimal expenses ($20-40k/year). Requires ~$500k-$1M.
- Coast FIRE: Enough saved that compound growth handles retirement. Work only covers current expenses.
- Traditional FIRE: Full financial independence. Work is 100% optional. Requires 25x expenses.
- Fat FIRE: FI with a luxurious lifestyle ($100k+/year). Requires $2.5M+.
Why Coast FIRE Changes Everything
The psychological shift of reaching Coast FIRE is profound:
- Career flexibility: Take that interesting but lower-paying job. Your retirement is already handled.
- Reduced stress: You don't need to maximize income anymore. The pressure is off.
- Better work-life balance: Work part-time, take sabbaticals, or freelance on your terms.
- Pursue meaning: Teach, create, volunteer, or start a passion business without financial anxiety.
- Geographic freedom: Move somewhere cheaper and more enjoyable without career concerns.
How to Reach Coast FIRE Quickly
The fastest path to Coast FIRE:
- Start immediately: Every year of delay significantly increases your Coast FIRE number
- Front-load savings: Save aggressively in your 20s when compound growth has maximum time
- Use tax-advantaged accounts: Max out 401(k), IRA, and HSA for tax-free growth
- Invest in low-cost index funds: A 1% fee difference can cost hundreds of thousands over decades
- Avoid lifestyle inflation: Keep expenses stable as income grows
The Coast FIRE Lifestyle
Once you've hit your Coast FIRE number, life looks different:
Imagine working as a barista, yoga instructor, freelance writer, or part-time consultant — earning just enough to cover rent, food, and fun — knowing your retirement is already fully funded and growing. No 401(k) contributions needed. No savings anxiety. Just living.
Many Coast FIRE practitioners report that removing the pressure to save actually makes them more productive and creative, often earning more through passion projects than they expected.
Risks to Consider
- Market underperformance: If returns average 5% instead of 7%, you'll fall short
- Inflation spikes: Higher-than-expected inflation erodes purchasing power
- Lifestyle creep: If expenses rise, your Coast FIRE number was too low
- Healthcare: Early career changes may mean losing employer health insurance
Mitigate these by targeting a slightly higher Coast FIRE number (add 10-20% buffer) and maintaining some level of income-generating activity.
Calculate Your Coast FIRE Number
Ready to find out if you've already hit Coast FIRE? Use our financial independence calculator to see where you stand. Enter your current savings, expected returns, and target retirement age to discover how close you are to coasting.